well Im not sure if Kishiyo is stuck on a template... <_< looks like QBZ-95 to me
hard to say as Saint Louis (also by him) defies that, though looking at his greater body of work, he's prone to certain things.
I actually wonder if someone among the devs found Maya lacking (she's not entirely unpopular, but no match for her fanservicey sisters) thus having Choukai made closer to the more popular sisters.