Even as a hardcore Batman fanboy, I hate when he’s an infallible unstoppable Bat-God. Grant Morrison is the worst offender, but tons of writers have done this.
Similarly, Batman being an aloof, paranoid jerk isn’t cool or interesting. It just makes him an exhausting character to have as a protagonist. I mainly blame Greg Rucka for this, though Rucka at least seemed to be doing it on purpose to make an actual point about his bad behavior. Mark Waid also had a hand in that with Tower of Babel, but at least he tried to use that as a basis to develop Bats out of his jerkiness (and other writers ignored that development because “Isn’t it cool that Batman knows how to beat up all the other superheroes?”).
Writers need to stop trying to reinvent Wonder Woman and just focus on filling out her rogues gallery and supporting cast, both of which are rather sparse compared to the rest of the Big Five.
Wonder Woman should probably be the leader of the Justice League.
Superman doesn’t necessarily need to be happy all the time, but should at least be heroic and idealistic. Otherwise, it’s just missing the point.
Superman’s power level is at worst an exceedingly minor obstacle to telling stories about him.
And finally… Superman and Batman’s costumes look really ugly without trunks.
(Oh, and Batman should have his yellow oval, too.)
(And for that matter, Wonder Woman’s classic eagle symbol both looks better and makes more sense than the layered Ws.)