User blog comment:Nekonite/whats up with all the echo fighters?/@comment-416633-20190531163957

Echo Fighters allows them to add characters who are very similar to other ones that already exist. Ken is literally a clone of Ryu in Street Fighter so it makes sense in that regard. In every game that has both Peach and Daisy, their stats are the same, and their signature moves are the same, just slightly different (Peach's icon is a heart, Daisy's is a daisy). Dark Pit is the evil version of Pit in Kid Icarus, so it makes sense for them to be echoes.

It's not being lazy, it's allowing them to include characters that wouldn't normally be considered unique to have as a stand-alone character.