Flash is Central City, the problem with Flash is there are no actors capable of playing him in a live-action role. That and he's actually one of the most powerful characters in the whole DC universe thanks to some writers really exploring the extent of his Speed Force stuff.

Aquaman's biggest overlooked power is his Telepathy; Yes he can talk to the fishies and tell them what to do and all. He does this to people too, in fact one of the bigger cop-outs people could bring us is that Aquaman can very easily get out of any situation via professor X-ing them into a coma then punching them with his super-strength.

Also the big trick with Superman isn't necessarily to nerf his powers but to put faith into the character's ability to draw audiences. He's iconic even now, and I think adding a lot of unnecessary religious imagery (Superpope jokes aside) and baggage can detract from his story as an outsider, a god among mortals trying to protect them while adhering to a moral code that they'd find acceptable.

that's my two cents at least.