Some food for thought.
People seem to be assuming that Exar Kun - like Revan - has a vast amount of Sith on his side, he doesn't (or at least to my knowledge. Can anyone give me clarification on their numbers? I am sure they are not many. While the Revanchists must have numbered in the 100s. So the battles are not exactly comparable.
What made up the majority of Exar Kun's forces were Massasi Warriors and Krath. They were skilled warriors but then so were Mandalorians. And they had basilisk war droids, which would tear apart Kun's forces. I estimate the number of basilisk's to be vast. They were present in almost every battle so we can assume that 1/4 of the neo-crusaders possessed one - and more were in reserve.
Exar Kun may be extremely powerful, but he can only bring his full powers to bear on the ground. In space he is vulnerable.
If this is the case then the Krath warships and Republic technology go down in flames. Bassilisks are quite dangerous, more firepower than any starfighters of their time, able to take down ships much, much larger than themselves, and they are war mechs, not just vehicles. Semi-sentient, able to fight in melee range and bombard from a distance.
I don't really like seige scenarios, but are we looking at EK holding up at Y4? If so I call shenanigans. Mandalorians are known to sling-shot nukes, and they could bombard Y4 into a smoldering crater.