Against characters with one, unsafe wakeup, it makes sense to not worry about flash parry. The option becomes beneficial vs characters who have two or more different wakeups that serve different purposes, like Erron. I can see flash parry being strong vs them.
I'm not sure if people are understanding Ex buff in detail now.
If you do flash parry and absorb the wakeup you take a minimum of 14% damage as well as lose your knockdown followup or you take 20%+ in damage and continue your pressure on knockdown, your combo will do 43%. But if they don't wakeup then you've lost 1 bar, lost your pressure on wakeup, and start taking DoT since the flash parry can't be done on reaction to most wakeups.
If you just block/read and avoid the wakeup, you don't take any damage besides chip, your combo does 41%, and you get to continue your knockdown pressure.
There really is no comparison here. Pre-patch the move was good since it actually did more damage and didn't drain health. Now Ex Buff is just a lazy man's tool in every way. If you want damage then do optimal Ex DB1 combos, if you want pressure then use Ex knives, if you wanna blow up wakeups then just block.