Maybe it's all placebo, or a combination of dumb luck and bad players, but I have noticed that I'm not dying from "wanted" bullets as much as before. Also, the players that I meet 1v1 are mostly favored my way. I pull host about 90% of the time.
Can't say anything about sbmm, I have two accounts I play on. One is a 5th prestige and the other a lvl 41. Haven't noticed a difference in the two regarding lobbies. I always get a mix of both 1-2+ kdr players.