She gives a bit more interest on special events. But the actual social link is more about her being curious what having a boyfriend is like. Still say they made the wrong sister a romantic option. Just imagine sae calling you out for falling in love with her during her social link.
I think the game should have dropped those "5 points at stat" checks for female party members Confidants. Not only because they're the most common characters people is going to romance (and the ones people usually try to level up ASAP, anyway), but because they unlock important skills during the game (including a new Persona).
The game seemed to give players a few events to hang out with whoever you choose (Hawaii trip, School festival and all), but I don't think a lot of people would have maxed stats by September.
I think they should have had the checks for party members (well, unless maybe Haru, which is a late option) at level 3-4 (so it's more like a "hey, have you been managing your time well enough?) and lock those 5* walls behind other character that, while useful, don't have get as many special scenes due to not going to the same school as you.
I would have done something like this:
Ann and Ryuji: 2 stat check.
Yusuke and Makoto: 3 stat check.
Futaba and Haru: 4 stat check.
Did Persona 4 Golden had the same kind of "walls"? I don't remember having the same issue when playing that game. I do remember Persona 3 being pretty brutal in that sense. You couldn't get to level 1 unless you had X stat at max.