Please take Ranked into account!

So I just played some devastatingly one-sided Team Builder games (see attachment). One flaw with normal matchmaking is that it can only use normal MMR. But what if someone plays ranked almost exclusively? In the attached game, we're facing a Diamond 1 player using their main role. This person might not play normals ever and so maybe they have a gold MMR even though they're actually much better than that.

My idea: If a person's ranked MMR is dramatically higher than their normal MMR, take it into account by averaging the two MMRs and using that instead as their normal MMR. I understand people will use normals to try new things or queue with friends, so I don't think it should use 100% of the higher MMR.

Would this idea help make more fair matches?