One individual acting crazy in a batsuit is conventional based upon the Batman's context as a character--not to mention his setting, et al. Whether or not it's a silly idea depends on the specifics of its execution.
Batman Inc on the other hand, is through and through an unconventional idea as it involves an unprecedented amount of vigilantism sanctioned by that one crazy individual. As such, I'd consider silly in a more negative context than Mxy would.
Morrison's still at the helm of Batman's entire continuity and he still sucks......Big surprise.
