Almost every time I see bands play live, I see guys who can play faster and flashier than each other, but half decent rhythm players really are few and far between. No wonder that Malcolm's genius was under-appreciated.
I remember reading interviews with Angus where he was constantly singing Malcolm's praises, saying that what his older brother was playing was actually much harder than his own parts and crediting him with dialing in his tone in the studio in the early days.