A couple things I want to suggest. Sorry if any are repeats:

1) I'd really like to have another tank besides Thancred. Perhaps even a female one?
2) It'd be nice to have a female healer as well.
3) It'd be nice to have one or more male DPS peeps -- another melee one would be nice, for example.

Just for those situations where you want to have "all girl squad" or "all guy sqaud" because, you know, reasons.

4) I really, really want to be able to tell them to prioritize a mob. Those gremlins in Holminster's Switch... tanking those things in Trust is a nightmare.
5) It'd be nice if they all had at least one AoE move they could use every now and again to speed things up just a wee bit. Like Y'shtola's Thunder could be Thunder IV AoE version instead of single target. Ryne might have something silimar to Circle of Scorn on PLD, etc.
6) While personalities are nice and all, I worry about how it might affect things in the future and hope that you make considerations for them. For example, the final boss of Dohn Mheg. Ryne and Auphinaud walk across that line *very slowly* and barely get to the Finale area in time to do any damage. Fortunately, Alisae runs right over there, Thancred teleports, so does Urianger but he takes forever to do it... Y'shtola is faster than Ryne but she still takes quite a bit of time to get there so if you happen to have picked a slow combo and you're on a low DPS job-- tank or healer-- you might not be able to get it in time. I'm not sure how other dungeons might be, it's the only instance I've noticed that it could really make a difference.

[Bug]?
Y'shtola and Auphinaud seem to have trouble with the second boss of Dohn Mheg. When coiled ivy comes out, they sit and DPS the boss rather than get themselves out their bindings like others will. I'm not sure it's intentional, but it certainly doesn't seem so because it causes them to eat a Swinge or fail to get to their tether-line-thingy for the growth mechanic. If you use both of them on any given run, I can see you becoming very frustrated with that particular boss.