If you are looking to bump up the flavor a bit, and you are looking to deviate from the German/Octoberfest spirit a bit. (I am assuming by your more hops idea that you are) Then try anywhere from a few ounces to a half pound of Pale Chocolate malt. (Not the full 350°L, but pale chocolate) The roasty character can add a really nice flavor while still keeping the malty tast that makes it an octoberfest. The lighter kiln give the roast a much more subtle character than "normal" chocolate malt.
In my opinion, if you add enough additional hops, you will wind up with more of a German Alt than an Octoberfest. (Both good beers, but O-Fest is about malt, while the Alt Beer gets a bit more hop character, but not to the point of a Pale Ale) So I would go in one of the two directions... add some roast or add more hop quality and instead of brewing an "Imperial Octoberfest", brew and "Alternative Octoberfest".