Agreed. It's hardly a "must-watch" for fans of the oiriginal. It's a "stay the hell away if you thought the original themes and character arcs were meaningful and well crafted".

Because it's what I call a Cannibalising Sequel: instead of easily flowing from, and enhancing the old story and making it better (think Godfather 2, or The Empire Strikes Back), in order to prop itself up a Cannibalising Sequel ruins the old story retroactively, taking away the importance of things that used to be meaningful (think Starcraft: Brood War, or Alien 3). Important sacrifices, past decisions which were supposed to have lasting repercussions, character arcs, lessons learned, and the prices paid for them... so much of that goes out the window in Rebellion.

It's also poorly paced as a movie and sloppily told as a story. The original Madoka had more of interest to offer in its first 2 minutes than this thing has in its first 20. I'm not exaggerating.