When Bill Burke was CEO at MIA he had a plan to build a light aircraft taxiway to the threshold of both 27 and 09 to avoid backtracks.
Maybe so, but it is the RPT aircraft that do most of the backtracking and any proposed taxiway should be suitable for at least the D8 and Saab types. I don't think we will see a 737 there again for some time? It is already a problem for the RPT's when the school are out doing circuits on any runway, especially with their poor English skills!
The ILS could be aligned with 27, but it will be at a cost that obviously they don't want to entertain when it is there in the first place for the flying school as history shows that it is not needed, especially on 09.