I agree that Rask is younger, but at the same time as we found out he is not completely play-off ready. He is a fantastic goalie, but still not as good as freshly recovered Tim Thomas. Thomas looks better than any goalie in years, he plays as if he was in a 20 year old's body. He has the experience that we need to make it deep into the play-offs. He is the better goalie of the two, and besides we have an nhl ready goalie in the minors right now. It's not fair for him to ave to play down there while Rask remains underplayed at the NHL level.
In short my opinion is that we move Rask in the off-season and try to get a young puck moving player in the trade. Thomas is amazing, you can't give that up. Look for Khudobin to see some NHL time soon.