Most of them would’ve played like ass in SFV. The EX cast are designed to work with the EX systems and would have to be tweaked a lot to work in SFV.
Take Shirase/Hokuto who I main, just to get basic stuff like Renshou Geki juggles in, they’d have to make it an EX. But what about Kiren Eki, which is one of the juggle options? Since it doesn’t look like it’ll work as an EX, it’ll probably be a V-Trigger. But she’ll also need a second V-Trigger, so, based on what they’ve done with other characters, they’ll make that turning into Shirase. But with either option, she’d have lost tools she’d normally have access to.