that's more character dependent than a Blazblue issue, certain characters have setups and combo that don't work on everyone (Amane and Kokonoe for example), so yes they'll have to modify their offence depending on the MU, but you usually figure that out b4 hand, not so much the middle of the game. even so most of the time it'll boil down to removing a combo filler to reduce pushback or taking a microstep for a setup