I have the opposite problem. I can't get my account to stop climbing in rank other than to stop playing.
At some point the "skill" rating system decided I didn't belong in Seeker and starting to rapidly accelerate my rating all the way to Emissary even with an abysmal win rate of 20-30%. That's because wins were enormous jumps through entire ranks but losses were a drop in only 1 subrating at most.
Skill, experience, or wins really don't seem to matter to the skill rating system. I don't know what metrics they use to determine how good a player is but it doesn't seem to be working. Perhaps they are experimenting with different metrics for different players?
Or maybe it's because I play a wide variety of heroes and none of them have red or green arrows (all of them are double grey down arrows, even my most played) and that's messing with the system somehow?