Perhaps the courts will have to step in clarify? But this won't solve the administrative issue. If agencies don't have "agency" to do their jobs well, that would be ironic.[1] Perhaps Congress will be motivated to write better laws?[2]
[1] I'm deeply suspicious of efforts to undermine agencies under the cover of "only Congress makes law"... I suspect is it often a guise of undermining the laws one party does not like. Or, sometimes, even as an effort to undermine the idea of regulation at all. The latter point is hardly hidden -- it is central to a lot of right-leaning rhetoric which seems to boil down to "regulation bad, freedom good". This level of reasoning would have Milton Friedman rolling in his grave, as some regulation _provably_ helps reduce market failures. (And even center-left people typically want markets to work well.) But I digress.
[2] Hah. The idea that we would give Congresspeople and their staff even more responsibility to specify laws _without_ an associated increase in their competence for those areas where the law applies strikes me as foolhardy.