Hand drawn sprites in the HD era are expensive.  Characters can have up to 3000 different stills of animation to draw, and it's extremely time consuming.  You need multiple artists per each character.  It's why king of fighters, and guilty gear also moved away from spites.

Not only that, it's a lot harder to sell palette swaps for a character, than it is to sell a new costume.

Look at the amount of costumes that are in Street Fighter V.  Doing the same for sprites isn't feasible, because you may as well just create a new character.

Sprites are expensive, time consuming,to the general public they make the game look cheapened, and you can't sell any meaningful DLC with it.

Far too many negatives, and Street Fighter, nor any game is ever going back to sprites after going 3D.  Though, King of Fighters somehow managed to find a way to look about as good as an early GameCube game, so if there was any game I'd like to see go back, it's that.