For anyone that has seen the Episode III, we see that Greivous was an actual human that was kept alive by robotics. Would it not have made the films tie together beautifully if when they panned in on Greivous' eyes, the red and black of Maul could be seen? Gives a precursor of how Palpatine would save Vader in the same way.

Obviously it didn't happen, and some may think it stupid. But I think it would have made Maul's character have some substance other than to get 10 whole minutes in the first film.