I'm sure people know this guy already, and I apologize if these have been brought up before, but my searches couldn't turn up anything so...
I thought I would try to put the word out about the videos that brought me here. They were done by a guy named Maximilian (Miles923 is the youtube channel). The commentary is frequently... silly... and annoying... but there's quite a fair amount of practical stuff in here.
Highlights include:
-Aquaman's From the Deep can be punished on block by the Lightning charge from apparantly anywhere
-A number of mentions of the Flash's speed dodge accidentally coming out when using a stick and hitting db instead of d when crossing up. Alternate controls are suggested.
-The Flash's anti-air sucks. his d2 gets stuffed by seemingly everything.
-A glaring weakness to keep away, Green Lantern and Nightwing in particular. Green Lanterns Rocket Power (d,b,2) is notable, because of the awkward angle that makes jumping in risky, the ability to vary distance, and the meter burn version shoots a second rocket that does go full screen. In fact all of Green Lantern's keep away did between 17% and 20% when burned.
-The Batman Beyond fight in the 3rd video was pretty interesting as well. Batman avoided a lot of mixups by backdashing after doing a canned strings.
Based on these videos the key seems to be "Get in, and stay in." Flash did virtually all of his damage at point blank and was useless at virtually anything beyond midscreen. I could totally see the Speed Dodge becoming very important to maintaining pressure at higher level play, given the ridiculous punishment opportunities it provides. Conversely this means that anything the Flash has that pushes out is useless (mb speed dodge comes to mind).