I know there’s nothing much 343 can do to increase the player base at this point but I really want to complete the “Win 15 ranked matches in Halo 4” seasonal challenge and I can’t because I can’t ever find a game 
The hotfix they released today addresses that issue
If you stay in the lobby after a game you can wait for ages cause you are not going to be reconnected. If you leave search and go back into searching a game MCC will through you back into the menu straight away (bug).
So what I do is restart the MCC or sometimes even the whole console and then go back in.
It helps but I have to do it far more often recently and it sucks.
That’s the experience I am still making so far.