So you traded a low-print, limited distribution, console exclusive game that almost didn't get released at all to get the "latest greatest" Halo and now regret the fact you can't get your game back? Hard to feel much sympathy. Stop looking back and just move on.
Yes, you are missing a good game. Yes, there are dozens of other good games worth playing that are easily available. Wii U has already shown trailers for a game that appears to be the Xenoblade successor - when that comes out grab a copy and stop worrying.