Fifth: I wouldn't know, I haven't finished the game yet, and haven't looked at Ico. Didn't really occur to me they already made another game :/
Fnord: That is exactly what I was thinking about Guitar Hero III. There's no way they can abandon PS2, since tons of people already have the system and guitar (and not many PS3s have sold, but that probably wouldn't be a factor). As for a worthy sequel, it most likely depends on which songs they put in and whether or not they try to "fix" the game. If it ain't broken, don't fix it.
Yeah, as for all this SotC/Ico stuff, does Ico play like SotC? I would be interested in picking it up if it is a true game to the series.