Resistance is a sci-fi shooter with a deep storyline, which is rare for shooters. So far the series has been really good, and I expect 3 to be a 9/10 game. You probably won't understand the story without playing the first two, and possibly the PSP game.
I still believe there maybe a chance that Nathan Hale could come back but doubt he would be an ally of any sort. This looks promising and I am excited for the story and the change in multiplayer. R2's multiplayer was sort of a let down. I also hope they give two kinds of co-op. Like having the kind in R1 and an option of R2's type. Overall, I am stoked. This series has been amazing so far!