So i just evolved my first girl : 4* Casablanca. Not my favorite one, but the only red type character i had lvl 50, and today was the red dragon day in special campaign.
I have to say i prefer her awakened art so i'm really pleased, and i was surprised to see that when you assign her as assistant leader you can switch between the 2 different art post and pre AW.
She lost a little bit of her combat stats (e. g. HP 5000 -> 4400), and this despite the x2 bonus affection. Or maybe the stats we can see in the unit section don't take the affection boost into account ? I don't know this for sure.
And i have yet to get her to 100% aff anyway (54% currently), working on it.
She also gained a passive ability : +10% bonus damage to Solar blast. That means +270 currently for me, so not really game changing i guess. And i believe it only procs for her squad.
All in all, i think it is a nice feature, but the short term impact on my team probably won't be that big.