There are problems. Tiny problems that make huge issues. I'll name a few of them.
File share needs to be fixed so we can see forge maps in matchmaking (I like the map, but I'm tired of Haven). I would love to see an MLG playlist with Lockout in it (I loved this map in Halo 2, I tried it in Halo 4 and I feel it could work).
There needs to be more custom game options.
Forge has some nice new features but it needs serious fixing.
As for gameplay besides bitching about how guns aren't balanced I'll add something new: Take out auto pickup of flag/ball, descoping needs to replace flinch, despawning of weapons is too quick, I shouldn't have people spawn behind me after I kill them (I'm fine with instant respawn, but the locations where people spawn is ridiculous)
I can name other problems in the game. Don't get me wrong, I like this game alot(serious potential, I feel), but it has its flaws. I'll continue to play for enjoyment (like we all should since it's a game), and wait for the title update (which 343 announced btw).