I think that there are 2 big issues with the video:
1) The footage seemed fairly random with the muisc, and the clips were very long without much editing/cutting at all. Transitioning between one anime and another really was nonexistant. It went from Shinji Ikari to Tsubasa Resevoir Chronicle, and I nearly did a double take. In the same sense, I felt like you didn't sync well with the music. You attempted some lyric sync, but without taking the music's beat/flow into account, the video didn't have the same impact it could have had.
2) Visual quality. The video footage that you used were all different aspect ratios and video sizes. It just didn't look very professional or good looking.
This is a very helpful guide that might aid you in future projects.
Cheers and good luck.
