Students have access to OPT (1y) and STEM OPT (2y) on the same visa to work after their degree. If they go for a higher degree then they can get OPT again. Grad students from US universities also get a separate quota in the H1B cap.

All of this should to a little extent alleviate some of the concerns.

The weighted system should still work since the candidate pool (from within the US) is likely mostly students on OPT. They should have comparable salaries, unless they are hired by rotten companies.