Well, just about everything has been said, but I'll add my two sents.
Revan was a genious, and we know from the Starmap in Kashyyyk he was perfectly willing to make a sacrifice if it meant victory. So, thinking about that, I believe Malachor was, of course, a trap. It is possible Revan gathered all his fleet at Malachor to bait the Madalorians there. It wad to be a huge force to force the Madaloreans to commit the whole fleet.
Then, as the battle progressed, he probably divided them between those loyal to him and not who weren't. He might have sent the loyal ships out of the area to fake some kind of flanking attack or to strike somewhere else while the Madalores were engaged a Malachor (think the last Battle of Mon Cal in 'The Unifying Force'). And he had the Exile to activate the MSG, effectively wiping out the Madaloreans, and all his disloyal subjects including Jedi in one stroke.
He knew that Malachor would, one way or another, kill all the Jedi there. Death of such a large scale caused by Jedi would either turn them to the Dark Side or simply destroy them. Revan probably never intended for the Exile to survive, but I'm guessing he didn't anticipate the Exile would cut his link to the force for the sake of self-preservation.
It's all speculation of course. Feel free to disagree,