Help me with knowledge

So I would like to ask a question regarding matchmaking. Yes. There has been written a lot abou it. I have read some amazing tomes. My question: As far as I have read people say winrate/KDA does not influence the formula of matchmaking. But I would like to understand why KDA should not take a mark along with the other parameters in determining the pairs. I mean a KDA does not show everything, but certainly would fill out the 0-25 intentional feeders. And would really put help the better players stand out from the rabble. I am not saying KDA should be an emphasis, but can it/should it be a little bit more signifficant? The IT guys feel free to flame me with logic. As well as other. Just help me understand a bit more.