The only things I remember about Bane is him defeating Kas'im on the basis of force prowess and the strike team with Zannah's help. Then, again, I don't remember sh*t about the Bane trilogy other than the beginning of PoD.
Even accounting for Bane's Force advantage, he was still able to perfectly counter all of Kas'im techniques, which encompassed utter mastery of every sequence of every form. Bane's lightsaber skill and physical abilities are more established than Revan's imo so I'd probably give him the win.
On the other hand Revan does use dual blade style, which was Bane's critical weakness in PoD. While I'm certain Bane would have corrected that weakness in the decades afterwards it isn't outright stated so one could make the argument for Revan on that basis.
Kas'im abilites refer to technical mastery, which a good score of characters are also stated to possess and a sh1t ton of others are implied to have as well. Meanwhile, Revan defeated Malak in ridiculous unfavourable circunstances - someone who possess multiple all time accolades referring his power and combative capabilities and is also, holisticaly, much more recognized and acclaimed in the mythos than Kas'im could ever dream to be.
Well it seems established now that DoE Bane >> Orbalisk Bane >>> RoT Bane >> Freedon Nadd, which is a similar power chain to SoR Revan > KotOR Revan >> SF Malak >> Exar Kun >> Freedon Nadd. On top of that Bane seems to have far better specific dueling accolades.
That being said, it's still very possible that Revan is more powerful than Bane, but I'm not sure if he's a better duelist.