There are many modern games that are original - it's just that they aren't funded as much, and thus a smaller portion of the already smaller income goes to the marketing. Just look at anything the indie game market has produced recently. For example, minecraft, while I personally don't like the game, is a pretty neat concept. Not even just the indie market, but some big games are pretty innotive - Mass Effect 2, for example, delivers a story very seemlessly in a way never seen before in RPGs. Assassin's Creed is by all means a modern game - and it has a pretty unique, although boring, combat system along with a pretty unique overall concept. (Only the hitman series focused itself on realistic assisinations as far as I know of, and that was during the present day)
But I do agree with you on one point, shooters are not really innotive this day. Compare it to Halo back in the day - there were some really neat concepts in that game. Tribe, Unreal Tournument with its wacky weapons, etc. You're seeing less and less of these and more semi-relastic gritty shooter games like COD4 with little orginality. There are a couple of games that expand on this concept, like Singularity, or Just Cause 2, but they don't really go far - and there aren't many of them.
WALL'O TEXT, I LIKE DEM!
Still playing LoL btw, anyone here play it too?