then with Revan who Sion thought was weak for turning down the chance to rule/fix the galaxy (or something along those lines) but left.
Pretty much. Sion wouldn't listen to anything Revan said the way he did with the Exile, and the only reason the Exile managed to get him to do it is talking about how Darth Traya didn't give a **** about him, which was something that is specific to that particular situation.
"There is something going on in time and space, and beyond time and space, which, whether we like it or not, spells duty." -Winston Churchill
"For of all sad words of tongue or pen, The saddest are these: 'It might have been!'" -John Whittier
"Apathy is death." -Kreia