I have not seen Rosen play except a few TV games at the WJC. But everything I've read throught the season and especially lately - including comments upthread and the Bill Hoppe piece linked upthread lead me to believe that this guy's got what it takes in terms of hockey IQ, speed, shot and attitude to be a success in the league.
Seth Appert said in the Hoppe article that he's been as good as or better than Kulich the last three months, that he's a driver on the team, and that he's attacking the hard areas of the ice as opposed to looking for the easy areas. He will certainly need to get stronger, but that type of attitude is not something to be simply disregarded and discarded. Rosen has faced an uphill battle around here because of his relative anonimity and obscurity when he was drafted - strike one. Therefore he was drafted with others on the board who posters preferred - which is strike two. Then strike 3 - his D+! year was totally FUBAR over in Sweden leaving stat watchers to see his numbers and consider him a bust and the top guy to be traded now that Mitts is off that list. So he comes over to NA, is learning the North American game and ice surface, is doing well and improving, and for a completely different reason - that he's one of our best prospects - is at the top of the to be traded list.
I just think it's way too early for that as we still don't know how good this guy can/will get. Neither does anyone else. So why would he bring a big return? He needs another year in the AHL, IMO - and as far as I'm concerned - hopefully as part of the Sabres organization.
All that said, no one is untouchable.