Hmm storyline... I think if they do bring revan back into it, they should bring him in towards the beginning rather than the end. like you can start it by talking to the council on courasant and they sense a disturbance in the force, and ask you to investigate. as you get to your desired destination (wherever it is) you are confronted by the dark image of revan (seeming regretful almost) as he wonders his old battlefields. as you try to get closer to him he senses you and (force power) disables you to interigate you, asking what u want from him kind of thing:- as you ask your questions he suddenly gets this feeling that me must leave and does leaving you unconscious, before you are found by another jedi (maybe one from the past) or even an old master of the character sensed you were in trouble. anyways you are partially briefed on revans story, and the main mission is to find out what he is back in the republic for.
The plot could see revan back in known space picking up the peices where he left off before going to the unknown regions. the exile is taking revans place on the front line of this new battle, giving revan some time to come up wth a conclusion on how to beat this threat. you and your companions learn of revans plans whatever they are being light or dark as u choose at the beginning.
maybe have to rethink this but its just off the top of my head