First, the dramatic music in the beginning is alright, but if you're convinced that a heart-felt, deep-feeling slow and heavy montage is the way to start this video, than have the image reflect he music. Slow the clips down (Full time, high-speed football stands in stark and unfriendly contrast to the largo/larghetto audio. Maybe slow the video down, put it in a softer sepia (as opposed to harsh greyscale) and add some nice feathering around the edges. Just ideas to make it fit better.
Second,the transition from the intro to the main video is sheit. The quick audio change coupled with the L to R 'arrow' fade is pungent in a bad way, get a softer fade for the music from one to the other (focus on keeping the measured beats the same for a few seconds to let the listener's ear adjust from one to the other) and the video transition needs more than a pre-designed fade. Perhaps fade one clip slowly out from LtR while the other, from the new season fades in at the same speed from RtL, even better, if you get both clips of the same type (pass, run, tackle, etc.)
Once you get to the main part of the video, it's not enough to just play music and highlight clips, you need to give us some transitions between the clips as well as line up the video with the music. Do your best to punctuate major points in the video (catches, hits, etc.) with major beats in the music (or at least lesser, as needed No one will notice if you slow down or speed up clips about 1.2/0.8x in the long run, but they will absolutely notice if the heavy beat of the music times out perfectly with a good, solid video of an amazing hit.
Looks like you've got a great foundation going though

look forward to seeing your future work.
FYI - I'm a bit of a pretentious little b***h when it comes to video editing, so don't take my words as strictly criticism, just things to think about as you continue to get better in your editing capacity.
GBR