My thoughts on Flash:
Flash’s costume is the one that I have the least problem. It’s very striking and very simple, no underwear or any other accessories that you have to reason out. Only minor tweaks from me here.
I always envisioned Flash as a Formula 1 race car – very sleek and durable. Not really evident here, but I am really thinking of a more sturdy material for Flash’s costume. It's something that could sustain the rigors of his super speed. That’s also the reason I gave him bulkier boots as well as some gloves for those lightning punches.
The mask could benefit from being one similar to the daredevil movie. Where there is something to protect his eyes, might be a good idea if you're moving pretty fast. I made the lightning on his ears sort of a comm device much like Bat’s ears.
That’s it.
Here’s another design from ‘08: