They wasted a lot of potential with the Killgrave character. I was expecting him to be a bit more fun and creative.
The show was also far too tame. In the comics when he is in a noisy restaurant he tells everyone in the room to stop breathing so that he can eat in peace, here in a similar scene he just says 'be quiet'. There were a few interesting moments though. They also completely avoided a lot of the sexual stuff, and completely re-wrote the Jessica and Killgrave history without even hardly digging into it. Just a lot of interesting stuff from the comics was dropped or re-written to make a more mainstream show.
I did still enjoy it, and probably preferred it to Daredevil, but it could have been so much more. Towards the end I thought they must be saving lots of interesting Killgrave stuff for season 2 but I guess not.