Yeah I just can't see a revote being the way here.You would need to at least propose again simply due to the need for a sponsor. I wouldn't mind them getting fast-tracked in case they do get a sponsor, though.
Now I respect the use case that a sponsor "delays" a proposal in order to "freeze" it (since you can't propose changes to something in flux in the current congress). I do think its an overblown concern, hehe if our dev team wanted to mess with things they have all the power to do so....but it is a use case that could happen.
So I think the answer is....the proposal goes to a new sponsor. If a new sponsor picks it up, than we proceed with implementation. If no sponsor picks it up, then the proposal dies due to lack of sponsorship. The key is it must be a NEW sponsor, that prevents the concern above.