I'm only expecting an 8.5 review score and about 3 million in sales for ODST. I think Killzone 2 has already countered it.
IGN had some article on game series that had overstayed their welcome a bit, and I think the Halo series was one of them because the mini-pic by the article was of Master Chief. However, I haven't had much luck trying to find the article since I first saw it, and I didn't read it.







