Well first of all, FE6/7 don't have particularly deep stories.
I personally don't have much faith in IS' monkeys at the writing team. They only managed to not screw up Echoes because the story was already pre-written, and the director was strict about being faithful. Honestly, the stuff that IS made up for Echoes that wasn't in Gaiden is a mixed bag.
Hopefully, if they hire an outside writer again like with Fates, they don't shit all over his/her draft again.