Not to turn this into a full-blown argument, but neither Bowser nor Ganondorf are 10 feet tall nor is Ridley 12 feet.
I'm not saying that scaling down Ridley is impossible, especially since it happened
within a Metroid game (Prime 3) and
this treasure of a beta animation exists for said game:
(Seriously, this is even more egregious than the Meta to Omega switch in the final product! Not that it's a bad thing; it's....
perfect.)
...but Bowser and Ganondorf were only
slightly scaled down in comparison to the hypothetical sizes people make for "Roidley".
(But of course, the beta animation Meta Ridley is just the right size.
Yes, I'm going to shamelessly promote it.)
In Meta We Trust!
Let "Roidley" be a boss. Have Meta be the playable one. After all, organic Ridley and Meta Ridley co-exist in the SSE...