For most modes, K/D isn't the most important stat in BF. Lol I play with one of the top medics in the game, his K/D is abysmal, but he causes us to win matches because he revives 80+ people per match. Lol
Or me, I get 1.5 to 2.0 K/D, but I also take out many vehicles per game solo (which is a dangerous activity, so I die more often); you would not want me with a bunch of new players because my K/D isn't super great.
Only stat that matters in my opinion in BF is Win Rate. Hell, even score only matters so much. I've had people with low score, but they defended an objective all game, and we won because they were there doing the "boring" work of defending an objective.
And this is why SBMM just doesn't fit in BF; personally, I wish they'd get rid of matchmaking all together and just give us proper server browser and official servers (quick match finding can still exist, but all it does is throw you into the official servers for the modes you want to play based upon ping).