Ehhh, I don't think Echoes and 3H cutscenes should necessarily be lumped together, even if they're similar in certain ways. Each game had cutscenes done by a different studio, and visually they both look completely different. Echoes cutscenes look really ugly in addition to the bad choppy animation (pretty much the only major visual blemish on an otherwise great looking game) whereas 3H cutscenes actually look really good visually imo, it's just the terrible animation that hurts them.
As for the style FE4R will go for, I think it'll be something completely different than anything we've seen before. Hopefully the animation quality will lean more towards Awakening/Fates/Engage than Echoes/3H tho lol.