A month ago me and my friend played the Streets of Rage collection on XB1 (via backwards compatible Xbox 360) and Streets of Rage 2 holds up very well. I honestly don't think it needs a remake if there is not one already. The music sounds amazing on a theater system. The graphics look as good as you would see a new indie game trying to capture the 16 bit look. So, no need to change the amazing artwork imo. And the gameplay is one of the best beat'em ups from that that era. It's a blast to play with a friend couch co-op.
Streets of Rage 2 is the seminal side scrolling beat 'em up to me and like Rosindale said, still holds up extremely well (as does X-Men the Arcade Game and to a lesser extent TMNT 2).
Also, this Axel art is looking pretty Jean-Claude Van Damme-y right?