He barely survived against THE Soresu Master and The Chosen One. That's pretty good if you ask me.
Good points, but I disagree concerning speciality in troops.
I think Revan can easily encounter Greivous in a duel. Look at how many times Greivous was forced to engage Anakin and Obi-wan. He barely survived most of those encounters. Just imagine Greivous vs Revan + tons of Sith assassins + Malak (perhaps?).
And I'd like to make the point that Revan's armies are large ENOUGH to hold Greivous at bay for a while. Long enough for Revan to try several assassination attempts and tactics.
How exactly is Revan going to get assassins to Grievous. Revan doesn't possess stealth. Not to mention that guard droids may be able to see stealthed assassins.