The amount of flashing is the same as Skullgirls for console and PC, and there haven't been any issues with photo sensitivity or things like it there, so I think we're mostly in the clear.
If anyone does have issues with the flashing on round start and such, I would love to hear from them!
I sometimes get migraines from flashing lights, or sometimes just finding them unusually painful to see. For a first order estimate of the scale of my problems, I was left in pain for days by the new Incredibles movie. Yay! I also find a variety of flashing color changing toys people love to give my 6 year old completely unbearable to be around.
I generally have not had problems with this game though, except for one week where I was already having migraines. That time I had to quit playing the game entirely for a few days until that cleared up.
Flashing round start was an issue, so were various moves. I confess I've mostly blocked out those memories so I don't have an exhaustive list of what caused problems, and I'm not about to induce a migraine to review the moves further
I'm not entirely happy with the new feature where characters start flashing colors rapidly after being hit by various effects, but that hasn't caused me any problems so far. It might though if I'm already having a migraine, but as stated before, the game's already impossible for me to play if that's the case.
Hope that's helps!