To be fair to Echoes, that was a near total remake of Gaiden, a game from 1992 that casual FE fans really only ever regarded as a weird black sheep. And most of the characters from Gaiden never even had proper official art. It only benefitted from being remade. And the remake did a lot of new things, even if a number of elements were direct revisions of ideas that hadn't been revisited since Gaiden, like the dungeons, town exploration, dual story paths moving in tandem, and the like. Its combat also wasn't afraid to harken back to Gaiden with the lack of the weapon triangle (and axe-wielding player units in general) and a magic system that relied on HP expenditure instead of a stack of tomes. The game also introduced turn-rewinding.
As much as it is a remake, it was shockingly fresh for ideas after Awakening and Fates.