Personnally, I don’t think so.
Man, even in Gen 6 I would’ve preferred Talonflame with Flame Body. I mean, Talonflame already has very high speed, so he’ll get to use most moves first, even without Gale Wings.
I think Flame Body is much more useful, you get 30% chance of burning your opponent when he uses contact moves, which means halved Attack.
So, no, I don’t think Gale Wings is worth it in Gen 7. I wouldn’t even use it in Gen 6 so...