The reason that they don't fix the lag issues is because they can't. The idea that the host should not have a blatant advantage is a great theory that falls short in practice. The players that use to teleport now just make everyone in the game lag; instead of kicking them, the game lets one bad apple spoil the bunch.
Wrong.. I used to get host in MW2 all the time and I never should have host. So there goes your theory out the window. My connection is not suitable for any sort of match over 3v3. Yet in MW2 I would get host for groundwar 60% of the time I played once I played more than 8 games of it in one lobby straight. So no matchmaking was not better, it did not choose better hosts all the time.
MW2 had just as bad lag as this game does, it just showed it differently and reacted differently to it than this game does.
the main reason this game gets laggy is poor host selection, a few of my friends and I have fibre optic 40up 10down and better internet speeds and it still picks the guy running the hamster wheel connection.
I know its more than just the upload and down load speeds that affect the hosting but whenever any of us have host its always fine.