There shouldn't be anything in the chosen implementation that prevents generics on methods. The work just hasn't been done yet. There are only so many hours in the day. Feel free to jump in if you have some to spare.

A wrong implementation would hamstring making such improvements in the future. It is possible that will still happen in some unforeseen way anyway, but the earlier proposals visibly exhibited problems from the get-go. They were clearly wrong. So far, this one does look right.