If I had to simplify my issues with DC over the years, they could be summarized as "putting positive characters who have no place in a depressing or serious story straight damn in the middle of one" and "Editorial revamps with no sense of respect for the fans of what has come before, or of the history of the characters".
At a panel, when I used the word "positive", Dan Didio challenged me to define it. I define it in this context as lighthearted, fun, more smile-inducing than sadness, and generally a character than I prefer to entertain me, rather then emotionally move me.
In no particular order...
Ted Kord - Just for SO many reasons... More than any, Ted's BOOM! Headshot was representative that has happened at DC too often - taking a basically fun, positive(*) character and placing him in a far too Grim-n-Gritty situation. Ted could easily be used in dramatic and emotional moments, as his appearances in BoP showed.
The fact that he's kept making more appearances AFTER his death than before shows (to me, anyway) that DC knew they'd pooped the bed on this one, and kept teasing him to show up again to appeal/take advantage of the Ted fans. The Blue and Gold issues of Booster Gold are a delight, with Ted being back to the way he was, and should be, but I just knew he wasn't back for good.
The Trials of Shazam! is another example of this concept. Captain Marvel is as "positive" a character as there can be in the DCU. What they have done to the character and the Marvel mythos in Trials is just anathema to me. There is simply no NEED to grit-up Captain Marvel. The fact that the events with Mary Marvel wildly diverge from the events and explanations in Trials is VERY promising to me. Especially if the SHAZAM movie moves forward, I am very hopeful that all of the events in Trials will eventually be explained away. It sort of started getting undone in JSA recently, but that got kiboshed fast. Freddy Freeman is appearing in JLA Cry For Justice, and I believe will be appearing in James Robinson's JLA title. That's great, but I don't see how getting rid of Shazam and promotong Billy made that possible.
As many have said, "Everybody is SOMEBODY'S favorite character."
The idea of making you care about a character and then killing them is far from new, and does not just appear in comics. But the issue is, once you kill them, any chance to use that character again for MORE good stories ends. (well, okay, no, but you get my point)
The argument I make is that death is not the only way to further a story, and should not be used as often as it's being used at DC right now.
Consider - Beetle's role in Countdown to IC was to discover the plans of Max Lord and alert his fellow heroes. How did killing Ted make that job go better?
Suppose he'd only been captured and incarcerated. Or actually shot in the head, but survived. Sasha sends the goggles to Batman. It's still proof that Beetle is in dire straits(Joy Division, even...), MAYBE dead. The heroes mobilize, all the same things occur. But at the end, they find Ted (on life support maybe) and save him.
And if you claim that it would be a cheat to not really kill Ted, how is more of a cheat then how they didn't really kill Ollie Queen in the GA/BC wedding special? I could rattle off a LONG list of people who supposedly died in a movie, only to be fine and dandy at the end (Here's two - Centuri in Last Starfighter and Duke in GI Joe the Movie). Why did nobody call those cheats? Hell, why did no one complain when Booster wasn't really dead?
Simple - because people WANTED THOSE CHARACTERS TO SURVIVE. David's Law says it best: If the readers wants a certain event to happen or a certain character to survive, they will forgive ANY damn fool way you do it, because you gave them what they wanted.
As far as I'm concerned, what they did to Booster they could have (and should have, and may yet be) done with Ted. They made Booster interesting and relevant again. They breathed life (literally) into a character that was a footnote and a joke. And now he's got one of the better-selling books DC has, or at least better selling than more well-known characters. It was, in short, a waste.
Ted got bitch-slapped. He got fired one day before his retirement and lost his pension. He waited in line to meet Clayton Moore just as he grew too tired to sign any more autographs. He got HOSED.
And as much as I love the new Beetle, as much as I enjoy the other books DC has done since and will do in the future, that is a move that I respectfully choose to refuse to accept. They dropped the ball, they traded the cow for beans, they had a gold medal and got it bronzed.
Kyle Rayner - The vitriol for today's editorial changes for the sake of change PALES before the acid spewed by comics fans over the out-of-nowhere embaddifying of Hal and handing the Power Ring to a random guy on the street named Kyle Rayner.
Really the first of the slash-and-burn, "we don't care what it affects, we'll worry about it later" moves DC had done in the modern age of comics, the move pretty much disenfranchised an entire generation of readers who were told their character was out, and this new guy was in. Heck, not only was Hal gone, the entire Green Lantern Corps was gone - the Guardians, all of that history, done.
And try as I might, I just couldn't get interested in this new guy. Yes, years later he's grown into a more complete character I could read about, but it wasn't until Hal (and Guy) and the Corps of old was back could I really appreciate a Green Lantern title again.
Sue Dibny - I get it. Adult story - they wanted to show a really repulsive act. And I must admit, it was a great story, and had a lot of effects in the DCU moving forward.
I just wish it hadn't been Sue.
I've said it a lot in the past; I've always had a sort of special affinity to Ralph & Sue, because their witty banter Nick-n-Nora relationship matches my wife's and my relationship (with the exception that she is not wealthy, and I am neither ductile nor a detective), so I always had a soft spot in my heart for them.
As far as I'm concerned, the story also pretty much ruined Dr. Light for me as well. Because to take a page from JoeQ's playbook, the act he did in Identity Crisis is far too "real world" for me, (not for any personal reason, blessedly) and put a level of true repulsiveness on the character for me. Much in the same way when they made Toyman a child-murderer in the 90's (a move blessedly undone by Geoff Johns last year), a move that could easily have made this list. If either were to have shown up in Blue Beetle now, for example, I'd be massively skeeved out.
The Legion of Super-Heroes - Possibly the best object lesson to the cliche "if it's ain't broke, don't fix it". Legion was DC's franchise, neck-and-neck with Teen Titans. They were the first two baxter-format titles.
And then Byrne came along and said there was no Superboy.
Now bear in mind, I LOVED the Byrne re-vamp, and everything that has come from it. He gave the perfect retcon for the issue - The Legion didn't start because of Superboy, they started bacause of the LEGEND of Superman, and all that he did. The past issues didn't vanish out of people's comic-boxes; any time they needed to be referenced in the current book, use Mon-El in his place instead.
But that wasn't ENOUGH for the folks at DC. They felt the need to explain it in continuity. It's like when you accidentally bang a hammer through the wall as you're hanging a picture. First you have to make the hole a bit bigger for the plaster patch to set right, then you have to paint over the spot, then you realize the paint doesn't match the rest of the wall quite right, so you paint the whole wall, and before you know it, you're buying a new house. So it was with Legion. They tried to re-tell those stories, then they insisted on re-vamping Mon-El to make him a bigger character, then they had to fix even MORE stuff, then it got so confusing they made a NEW set of legionnaires they could re-tell the stories with, they they rebooted all over, then they jumped five years into the future and changed everybody so much it might as well have BEEN a reboot, then they DID reboot again, and...well, you see what I mean.
DC had a hide-bound, fiecely loyal readership. But being shackled to continuity was more important than just telling good stories moving forward, and that readership slowly ebbed away, and the stories being presented just weren't as good as what had come before, so new readers didn't return.
Whatever will be done next by Geoff Johns will be viewed as Not Enough by some Legion fans, who have grown so bitter and despondent over the decade and a half-long reaming they've gotten that literally nothing will please them. For them it is too late.
Not following up on Crises - This is a harder point to explain. After CoIE, there was to be one earth, period. We started seeing alternate Earths (under the guise of "parallel dimensions") in under a year in Justice League.
Zero Hour was supposed to fix all the Time-Travel problems (not that anyone noticed any to speak of) in the DCU by severly restricting access to time-travel stories and setting strict rules as to how it would work. They were presented in Time Masters (a person can only use a particular type of Time Travel ONCE, so literally you'd have to use one method to travel one way in time, and another to come back) and were then soundly ignored as soon as someone had a good story to tell.
Day of Vengeance was quite close to a Crisis for magic - it got rid of all the rules on how magic worked in the DCU and would try to set rules for how it would work in the future. The rules are now being set up by each person as they go, with no sense of rhyme or reason. Zatanna'a powers have not changed one jot or tittle, yet according the Trials of Shazam, there are now a completely different set of gods that Freddy Freeman get his powers from. In short, no rules, no sense, nothing. DoV was a good story, don't get me wrong, but it ultimately achieved none of the goals it set out for. Reign in Hell was supposed to be yet another "crisis" for Magic in the DCU, but it sort of stopped being that almost immediately. All of nothing has changed as a result of the book.
I don't see any reason to restrict anyone's storytelling by saying that you can't have Thisguy do that because Thatwoman did that a couple months ago, but if you're going to keep a tight continuity, at least keep track of those discontinuitues, and address them internally. There's such a diverse universe out there that I have no problem believing in a countless number of different schools of magic or endless parallel worlds or variant technologies to allow anything a writer wants to happen. The mindset should not be, "You can't do that because" but, "let's see how you can do that if".