SakuyaA is kinda weird for some parts because she cannot kill an enemy quickly; so enemies WILL get shots off before she can kill it. It's pretty noticeable in stage 4 where the orbs -will- get their lasershoots off, while any other shottype can stop 'em >.o
She's really strong in other aspects though, so it's a a tradeoff.
It seems like MarisaA doesn't have much of an upside. Her bomb might be strong, but does that really matter? And she's just a forward focus like her B counterpart. As far as I can tell from testing in spell practice her shot really does do more damage up close, though (SakB doesn't). I'm not sure if it's enough to matter compared to, say, MarisaB straight damage output though. Hmmm. Maybe weird flamethrower mechanics have some kind of value. I'd have to actually try her out in practice more.
All the other shots seem like they have their own good values (even if SakuyaB's is just "Here is your godly scoring type because lolbomb, but it can't do much else"). NeedleReimu isn't -that- good but it combines Forward Focus and Homing, which has a good bit of merit in itself; Marisa's lack of range is a thing sometimes.