Looks like the 5th movie is where he and Suzuku will finally get more screentime compared to what they've got previously.
Unfortunately, I kind of doubt it: they have one hour left to wrap up the entire story, and I have a feeling Lelouch and Suzaku won't play a major role in it.
Episode 3 had me optimistic that we might learn more about the nature of Geass itself, as well as see more of Lelouch in action, but now that's looking less likely, IMO.
Then again, episode 2 only had a little bit of Lelouch, and there was a lot of him in episode 3. Maybe the little bit of Lelouch in episode 4 could mean we'll get more in episode 5.
But then again ... wasn't there no Lelouch at all in the first episode? Maybe that could mean there will be no Lelouch in the last episode.
I think we just have to wait and see.