I don't want to make fun because you never know what's going to happen in a player's career. I'd be surprised if Amendola ever becomes anything special in the NFL, but it could happen.
But I think looking back at what might have been is an exercise in futility. There have been several players we've "given up on" who went on to solid careers elsewhere, and there have been several players other teams have given up on that have done the same.
Jay Novacek comes to mind quickly. The Cardinals allowed him to slip away as a Plan B free agent after five mostly mediocre seasons, and where would we have been without him?