MenuProcessor can't cache
It's impossible to cache menu generated using MenuProcessor.
MenuProcessor Configuration contains invalid Arguments: cache.
Processing HMENU is an intensive process especially with expAll=1.
Using MenuProcessor actually means that the menu is processed at each page call (if the page is not yet cached)
Also, since actually MenuProcessor hard-code ACT and CUR, it could be useful to implement a feature that automatically caches the menu without ACT and CUR and then it overrides the cached menu, setting ACT and CUR over the cached menu.