Let's talk about Black Canary, shall we?
In this panel from Brave & The Bold #107 (1973), she and Batman are disguised as a stewardess and flight engineer, boarding a hijacked plane to take out the perps:
Mutant power? Great, call Charles Xavier, someone.
Well, Bob Haney, right? Still, this got me thinking about the (several different) origins of Black Canary's sonic scream, and what that might tell us about what works and what doesn't in DC's approach to continuity.
Dinah Lance started out as a non-powered crime fighter on Earth-2, back in the Golden Age. But during one of the annual JLA/JSA confabs, her husband, Larry Lance, is killed protecting her. Too stricken with grief to remain home, she accompanies the Justice League back to Earth-1 to start a new life for herself.
But lo and behold, it turned out that either a) the exposure to Aquarius' "magicks" during that battle or b) some radiation from that battle or c) some energy she hit during her crossing over to Earth-1 or d) vague references to something about differences in Earth-1's atmosphere or vibrational rate or some hoo-hah (we got some real dodgy brief "explanations" in the 70s), Dinah now had a sonic scream.
Eventually, though, someone realized that, as an Earth-2 denizen, Dinah had been around for quite a long time, longer than any of her Earth-1 counterparts. Given that by the 1980s she had to be in her 60s, that made her jumping around judo chopping folks less likely, and added an "ewww" factor to her relationship with Green Arrow.
There were plenty of easy ways to finesse this, so obviously, DC (via Roy Thomas & Gerry Conway ) ignored all of these in favor of the skeeviest one possible. If you thought Identity Crisis was creepy, well, this was creepy 25 years earlier:
Dinah and Larry, you see, had had a child back when she was still on Earth-2. But the villain The Wizard had put a curse on her as an infant, which gave her an uncontrollable sonic scream, which is a bad thing. So they gave to baby to Johnny Thunder's Thunderbolt, to try and reverse the curse. Well, he couldn't, so he just kept her in a magical coma (wherein she still aged) until a cure could be found. The T-Bolt also decided, because he hated to see folks in pain, to erase everyone's memories of this, so that everyone thought the child had died. Much less painful, obviously.
Wait, we're not done yet. It gets ickier.
So when Dinah decided to go to Earth-1, she and Superman (of Earth-1) discover that she is actually dying from Aquarius' radiation. So Supes and the Thunderbolt come up with the solution that makes the least sense: take Black Canary's mind/memories and put them into the still-comatose-but-now-fully-grown daughter, but make her forget the whole thing so she thinks she's still in her original body. Oh, and suddenly she can control the Canary Cry, well, just because. Freaky Friday, without the daughter getting to have any fun, as it were.
So, every time she was making out with Ollie, she was using her daughter's body.
Fortunately, just a couple of years later, the original Crisis came along, and wiped that slimy little retcon off the books. Now there were two Dinahs, mother and daughter, there was no body switching. And younger Dinah had her Canary Cry because she had the metagene, which was essentially DC's Modern Age version of mutants without the messy allegories. (Hey--Bob Haney was prescient!!)
Now, upon recapping this, my first thought it, this makes Donna Troy's problems look like chopped liver. Hawkman wishes his history were this convoluted.
Yet, DC made it work for Dinah. You don't hear people obsessing with Black Canary's origins, whining about which stories were cut or kept in the new version. You don't hear people opining that her history is too convoluted, that it's a barrier to people following the character. [Note: the jury is obviously still out on the nu52 version, because DC has decided that "easy to jump on to" means not giving any origins whatsoever] In fact, Dinah probably has as dedicated and loyal a following as any DC hero this side of Batman, despite the obviously rocky back story/continuity.
Maybe, just maybe, Black Canary is the Holy Grail, the one true formula: give her to creators who care about the hero; focus on building the character and not on tinkering with history (except, of course, for jerking us back and forth on whether she was a "founding" member of the JLA,); and she'll build a constituency.
There's no reason this couldn't be done for Donna Troy or any of the other "problem children" of DC's many reboots/retcons. Pick an origin story that works, ignore/wink at any problems, and just tell good stories.