Couple of things:
1. I trust economic incentives, not miners. The inherent uncertainty around changing those economic incentives is in large part the root of my dislike for this proposal.
2. Drivechains are still custodianship, just from an indefinite and dispersed group. You haven’t solved the peg out issue by tossing it to miners and please don’t pretend you have. Also if I’m going to have to trust a custodian I’d rather know specifically who they are rather than just “the miners”.
I recognize the need for scaling solutions, but this one ain’t it.