I have found this thread interesting.
While there is possibly a case to be made in limited circumstances (subject to a safety case) where an ATCO holding both ratings (APP Radar and AMC) could perform a "safe" operation.
Aviation is safe primarily because it uses evolution with harsh lessons to develop and refine its procedures.
All too often today the subtleties get lost in the mix.
An increasing number of decision makers lack practical experience in real life ATC operations.
Their understanding of the practical use of; application of and the imitations of technology being the most obvious.
One only has to look at some of the comments in other threads about the lack of understanding in some quarters as to what is possible/feasible/realistic or even safe.