SFML looks really promising good things for now and the future.
I am currently using the pygame Python library and some features would be interesting if implemented with SFML. I think about sprites groups. It also manage collisions (Only rectangles); so having collisions managed by polygons would not be too much. Having an integrated physics engine or a bridge with an existing one could also improve some games gameplay, even if others may not need it.
Anyway, SDL can render opengl spaces. Still in Pygame, using it make you unable to use both sprite and draw modules. What would be nice is to replace characters sprite animation by a 3d model making it smoother, but still exploring a 2d tilemap like Nintendo has done for both zelda and mario.
Making the first part (sprite groups) could be in my abilities; others, why not with time and good documentation.