That means he faced a few Jedi that never fought before...
Now you are right in saying those guys on Revan his ship weren't the most powerful Jedi of all time, they were incredibly powerful how ever. The entire Jedi Council on Dantooine says so when you talk to them about the mission, they all agree on the power of those people and that they were amongst the most powerful Jedi of the time in order to be allowed to capture Revan. Bastila is only there because of her battle meditation.
So Revan was indeed about to fight against some of the most powerful Jedi of the time, and he was not worried.
Now about the most powerful Masters, Kavar admits that he can't beat Malak, Revan his apprentice who couldn't beat Revan. Meaning Kavar can't beat Revan either. Seeing as Kavar is second only to vrook it pretty much means that the rest could not beat Revan either.
Kreia kills all those masters with just one move of her hand and she admits to being weaker then Revan. Yet still she does it without any problem. Doesn't that mean that Revan could do the same? Kill Kavar, Vrook, Zal Kal El or whatever his name was easily?
The Council on Coruscant is pretty empty when the Exile shows up there to be judged. Seeing as Disciple talks about Council members joining Revan I'm just going to assume the empty seats belong to council members who followed Revan.
Now they followed Revan they did not command Revan. They did not return to the Jedi after the destruction of the Mandelorians. And if they did you never hear about them, which would be strange considering how important they are. So they either died or they followed Revan further. Disciple talks directly about one that followed Revan even after Revan returned as a Sith Lord (he only talks about that one, because thats one the Exile and Disciple are both supposed to know)
Basically meaning that Revan had Jedi Councillors working for him, and they were to afraid to challenge him for control even as they embraced the Sith teachings. They couldn't even challenge Malak and he was weaker then Revan thats for sure. Sidious may have fought the most powerful Jedi of his time. Revan had them following him, or defeated them. Every single last one of those masters knows they are weaker then Revan, many admit to it. He would have killed them all, there is no denying to it. The Masters were lucky that they had always managed to run from Revan and that he lost his memory but Revan would have killed them all.
He has more training more experience and seen more wars. Sids would die