Whats with the ranking system?

I play slayer and team arena often. My slayer stats are as follows.
Kills-937
Deaths-579
Assists-464
Games-74
Wins-66
Rank-Diamond 6

Now someone explain to me why im still sitting at diamond 6 and cant rank up. I played and won like 20 games back to back beating several onyx and champs and barely moved.

you have a low kpm (most important stat)

I suggest you read through the OP of the pinned MM feedback thread and then post questions in that thread.