There may be down the road, but I doubt it. It mentions right in the game that there will be a Mass Effect 3 though, and you even get to see what you're up against; the Reapers.
Legion shocked the hell out of me on the first go... seeing as I played through the first one and imported my character. (which is awesome as hell, by the way.) I believe I said "What the fuck!?" when I originally saw him snipe an enemy. I'm not mentioning details cause of spoilers, though. I miss the Mako. The hammerhead is awesome, but you barely get to use it.
If you have yet to play the first one, I still recommend it. It's awesome that the game changes based on your actions in the first one, and even starts you off with extra stuff based on your level and wealth, etc. It says you'll be able to import your Mass Effect 2 character into 3 as well, so mine will have been carried over twice. Excellent.