These are five things that pop into my mind when I think of what I didn’t like. I’m not going to post things I consider nit-picky.

Biggest issue was the entire Starkiller Base plot-line. It felt like it was just “there”. If it was really needed (which is wasn’t), it was glossed over too much.
Thus I thought the pacing was almost too quick overall.
The whole Rathtar scene. It didn’t add anything worthwhile to the final product in my opinion.
Rey grasping the force so quickly, e.g. Jedi mind trick; feels like a deus ex machina.
I thought it was inconsistent with its tone in several places.