That seems non-orthogonal. We have an existing flag to force freezing (FREEZE); we don't need a second option that does the same thing. Skipping the index scans (and thus necessarily the second heap pass) is a separate behavior which we don't currently have a way to control.
It sounds like it might be better to name this "VACUUM (FAST)” and document that it skips some of the normal (and necessary) work that vacuum does and is only suitable for avoiding wraparounds and not sufficient for avoiding bloat