Just finished the game, gotta go back for a couple trophies for the platinum, but you're spot on. It's been a while since I played a Ratchet, but this felt EXTREMELY short to me. Like this should have been 40-50 bucks short. It's beyond beautiful, but if it took them this long to make this short 10-12 hour game I'd rather not worry about all the fancy graphics options and develop more story and gameplay so that I don't feel ripped off (Which I really think I don't, but man it's close).
Missions did feel like they all just blended together after awhile. Saw another user comment on the story not keeping you hooked, and I kind of felt that way after the opening, and it didn't really pick back up for me til the end of the game. Glad I played it, but there's no way I would suggest somebody go out and buy a console just for this game, and I did really enjoy my time (Wish there would have been twice as much)