I like the idea, but instead of losing points from winning against people with a bad spar ratio, I would suggest something different.

For example not gaining any points at all for a win, if Your spar ratio, compared to theirs is much better, but losing a ****ton of points if you lose against them.

I also wouldn´t exclude noobs from the normal streak room. Rather would it make sense to make rooms for people with more total spars and/or positive ratio.
If You win in these rooms, You would get more points per win, which would motivate players to spar in them, to get on the leaderboard quicker.