Granted Revan has a lot of options in this battle, but Traya's options are deceptive options. You are underestimating the effectiveness of psychological warfare. Once Revan devises tactics to limit the assassins, what remains is a psychological impact on the troops. You don't know where the assassins are, they could be right behind you, they could be watching you while you sleep. This causes a number of psychological issues for the troops. Paranoia, sleep depravation. These cause a serious impact on the mental fortitude of soldiers, causing lapses in judgment or even suicide, if a soldiers mental condition has worn away significantly. Such conditions can be damaging to an army.
But Revan does have options. Trying to wait out Traya could give him victory, but it could also destroy him. All Traya has to do is have her assassins pose a threat and the morale of Revan's forces will degrade significantly. This creates an opening for Traya. The only real threat to her Sith now would be the Jedi, and we know how effective assassins are against Jedi.
Revan's only option is to strike Malachor quick and hard, or prolong the suffering of his men. If he attacks Malachor, he will lose. Which brings us to this question: How does Revan win?
Not easy to answer. Attacking Malachor is foolish, and waiting Traya out will hurt his army moreso. The best thing to do is not fight. Draw her out and strike when she is not on Malachor. In this case, the decision by the Jedi Council to avoid fighting the Mandalorians is the best choice. Draw out the assassins and defeat them as they come, slowly wearing down Traya's forces until she is forced to send in the Sith Lords. Eventually, Traya will either give up or empty Malachor's Academy in an effort to win. Then Revan can strike.
But I think you also underestimate the power of the Force. Simply starving Traya and her forces would not work. The Force can sustain a being for any amount of time should they choose so. Traya could play the waiting game just as effectively.
You make a good point. I'll grant you that.
OK so it seems we've narrowed down the possible scenarios of this battle. Now I feel we've determined that Revan is too smart fully attack Malachor V. He could infiltrate, but that's another matter. And as for Traya, she's too smart to engage Revan in open warfare.
So what's gonna happen? Traya is gonna stay at Malachor V for the most part. This gives us that prolonged war we've been talking about. With that in mind, I'll elaborate.
Let's look at what COULD happen in a prolonged war:
1. Traya wins due to her assassins unbalancing Revan's army and creating chaos. This is unlikely due to Revan leadership and overall charisma. I feel he could keep his men in check.
2. Traya and her army begin to starve and experience an extreme lack of supplies. Many things could happen here, but they all mean victory for Revan.
3. After a long time, Revan figures a way to infiltrate Malachor V. This could end in many ways, but it would likely spell victory for Revan.
Once again, I feel that the only way Traya wins is through a BIG mistake on Revan's part.