He can dissolve Nihilus? Darth Nihilus' body is already dissolved and dead, corrupted by his own dark side energy, it wouldnt matter even if Vitiate could do that to him, Nihilus' very essence is incased in his mask and armor, and he doesnt dissolve things, he blasts them with lightning that disintegrates whatever it touches.
As for the fight between Revan being easy, I respectfully disagree. Revan was winning the entire fight from the start, The Emperor was terrified of him thinking he was going to lose. What Revan's mistake was trying to use Tutamis to catch Vitiate's full powered lightning and thinking he could overpower him like he easily did with Nyriss. Had he instead caught that attack with his lightsaber, this fight would have been alot closer. (Vitiate would still win 1v1, but with Meetra and Scourge, he wouldve won but they wouldve been killed by the Imperial guard after.)
Was Revan stronger? No if he truly was then he would have been able to catch Vitiate's full on blast.
Did Vitiate cakewalk Revan? No. Vitiate wouldnt have been so terrified if he did, He thought he was going to lose.
Also proof that the Emperor the JK fought was just his Voice: The Emperor was terrified of Revan during the fight, When he fought the JK he didnt seem to care whether he lost or not, like it didnt even matter. (I'm sure a sith would CARE or at least be scared if they knew they were or could be defeated)
Lord Emperor can dissolve even a force itself.
I dont remember him being terrified ( down below ) - and yes he would win even against 100 like revan. I find this book lacking integrity.
that is not exactly a proof as Lord Emperor is emotionless