Hillary is thrashing in congressional districts, which means the proportional delegates she takes will be more than 66% of the 214 delegates available in Florida. She will probably walk away with 150 of them.
Bernie staying in actually helps Hillary I think. Less amount of time for the GOP to focus solely on Hillary.
Extended primaries almost always damage the eventual candidate. The "making her a better candidate" argument doesn't hold true now, though it had merit a few weeks ago.