im an optismist. i believe in all possibilities. sidious killed his mentor out of cowardice. could he beat him one on one? he must not have thought so. and a bein his calibur died from bein thrown over a railing by a dying man. wow ok uh force levitate? im just sayin revan is smart and could formulate a plan that could win. 1% chance is still more than 0
At the time, I don't think Sidious could win. But in his prime, Sidious destroys Plaguies.
On the topic of Sidious' death. He died due to arrogance, which has killed many Sith. And it's not like he was falling for days. His body was destroyed only seconds after falling. He didn't have time to react.
I don't think Revan has a 1% chance. Sidious is a master of precognitive abilities and could see Revan coming from a mile away. i don't think Revan could plan for everything Sidious can do. But it is your opinion and I respect that.