I have to disagree about everything regarding inFamous being a sandbox game done right. inFamous is a sandbox with no sand: all you get to do are those side missions and collect things. Sure, the side missions actually serve a point in the game, but almost all of them are recycled story missions, and there aren't enough of the original ones. Plus, once you do them, they're gone. Then you just get to collect the random things, and... That's it. Yeah I suppose you can climb around, but why bother fighting with the awful climbing mechanics? There's nothing to do once you get up there. Grinding around isn't enough fun to warrant just grinding around for hours. And once you clean up the city via the side missions, there aren't any psychic hobos to zap in the nads anymore.
And in regards to who ripped off who between Prototype and inFamous... My money would be on inFamous doing the ripping off. If only Prototype had made its original 2008 release date, people wouldn't have to worry about such things. Of course, on the other hand, it might have been as bland and empty in the sandbox department as inFamous was had it not been delayed. I mean, at least when I'm done with everything else in Prototype, there's still both military and infected to screw around with along with just being a dick to regular citizens. And Alex's abilities are way more fun anyway.
Oh, and Prototype was much better written than inFamous, simply because inFamous decided to crap itself at the end with who Kessler turned out to be.