The nail on Ifrit can be difficult with an arcanist since most of our abilities are dots and you really need burst damage to down it fast enough. I pop Aetherflow and Energy Drain to give a bit more burst and managed it with two arcanists as dps. So yes, it's not as easy as say a thaumaturge, but it's still doable.
Cleric stance increases damage by 10% and reduces healing by 20% so it doesn't really help swapping your intellect for mind that way.
I've got both summoner and scholar and yes, all my points are in intellect, but with mind gear you can help make up the difference. I haven't tried any level 50 dungeons as a healer but managed up to Aurum Vale. Endgame is probably a completely different story however so if you plan on being a healer most of the time, I'd just reset your stats and dump them into mind.
Cleric stance increases damage by 10% and reduces healing by 20% so it doesn't really help swapping your intellect for mind that way.
I've got both summoner and scholar and yes, all my points are in intellect, but with mind gear you can help make up the difference. I haven't tried any level 50 dungeons as a healer but managed up to Aurum Vale. Endgame is probably a completely different story however so if you plan on being a healer most of the time, I'd just reset your stats and dump them into mind.