Let your algorithm listen to user input,...
if there is an error somewhere, what the right chord would be, where the song actually starts... in fact make it big and implement a learning algorithm like a neutral network or so.
Or I'll make it my own project sometime in the future :)
The Chord Edits feature has been released. You can read more about it on our blog:
Sounds like a very difficult suggestion to me! Apart from that, the idea is great! This functionality should co-operate with http://chordify.uservoice.com/forums/179340-general/suggestions/3918534-make-it-possible-to-edit-the-chords-change-chords