I used her in from Heaven to the true ending dungeon and had no regrets. Makaracarn/tetracarn helped a lot. Using mamudoon or mahamaon on normal battles made grinding a breeze + megidolaon on gold hands was very useful. Definitely NOT useless. This was without any s. link with Naoto.
Not to mention Naoto's Ultra Trigger critical hits and downs (I think) more than on enemy.
Edit: My first playthrough end party was Yosuke, Yukiko, and Teddie. I prefer a caster/support over physical attacks. Youthful Wind is just overall a great skill. Yukiko is Yukiko. Teddie is the most profitable choice for me because A)Ice Ice Baby, B) Backup healer if Yukiko wants to cast Burning Petals, and C) Junes Bomber.
Yeah I used to think Naoto was useless, but definitely not in Golden.
Yosuke is pretty much good at everything. He can heal, he can buff, he does decent wind damage, he does decent physical damage. I would say he's not necessarily great at anything, but he's really solid, and not leaving my party.
He's great because he's good at everything. --- I don't care what you say, Generation II sucks. That's just my opinion, no matter how true it may be.