I've only got some of my girls up to 11, haven't been paying attention much on it. Is it possible that they gain certain stat levels at specific levels? I know that a popularity, or "fast vs. normal" is supposed to make a difference, with the "fast" girls gaining levels quicker, but tapering off on the long run.

--And I know someone asked about it earlier, and I just figured it out myself (I'm sure a lot of you others had, too), but to change your Leader for your 1st Unit, if you click on her while in the Edit Team screen, and click "Modify," you're able to swap her out for someone else (ie: that 4 star freebie we got today). You can't "remove" her outright, but this is a way around it, it seems.

My top unit currently has 3 AR, 2 SR, 1 LMG. Seems to be working better now that I've got Iria out of there. Poor girl.
(Moved her to Unit #2 where she once again has resumed her role as bullet sponge. Come onnnn..)