Ranked – Need a new system?

As a discussion post, I'd be curious what others think:

Instead of having one rank for your account, I would like to see Valve implement a "role rank" for accounts. Meaning that each account, get 5 ranks. One for each role. MMR gained or lost, affects your rank for the role you played.
(Not entirely sure how to implement it for immortal+ that doesnt have a role queue system).

I would say it has several benefits:
1. If I want to try and practice mid, despite mainly playing support, I can still role queue (I.E be guaranteed to play the role which I wouldnt be in unranked).
2. I would also get a more appropriate rank for my skill level as a mid player compared to my ranked level playing as support.
3. Would make the balance of a ranked pub better, having similair ranked positions compared to todays when you get a guy queing mid for the 2nd time ever, and picks Oracle cause he just saw Topson play it.

Am I overthinking this? Is the ranked system fine as it is? Whats your thoughts?