Just thought I'd point out fates localization is better than awakenings and echoes added a bunch of memes in the translation like awakening too.
I think that it's a bit to early to say how much of an impact three houses until it comes out and even then it's hard to say what they'll actually keep, pair up looked like it might be a feature they'd keep using after it returned in fates, but echoes and three houses didn't bring it back and the next game probably won't either. So even if battalions or having full control on what classes the characters are come back in the next game it could just be something they use in a few games and then it disappears for the most part.