Yes, I agree that Brisbane could do with an upgrade on Scheuler as HC.
However, as I remarked re Mike Kelly being a very suitable AC but not HC, ditto for Scheuler, perhaps. Ever heard of the "Peter Principal" (highlights that personnel often get rewarded for being outstanding in a current role so gets promoted to a position which really requires a different skill set, so fail in the new role, put very simply)?
Scheuler was such a good assistant that he may have fallen into that "Peter Principle" trap.
So, keep him. His MU experience with Vickerman is invaluable and, in all honesty, Scheuler did well with what he took over. Brisbane was at a bit of a crossroads and he did well to pull them into basically a good roster. Just not one good at winning games. His roster seems engaged during games but also seem to lack passion and urgency on court. Get a new HC with the required skill set, not necessarily an experienced HC but one who can bring those mental aspects into Brisbane's game as a regular feature. Scheuler could then return to being a fabulous AC