(1) Wallstedt has played against players older than him most of his career. He was the youngest player to ever suite up for a game in the top U20 league (he was 14). He was the youngest goaltender to play in the top league in the Swedish Elite League. His record speaks for himself - and his record breaking career so far. It doesn't matter where he was drafted. I am looking at track record. Wallstedt himself dropped out of the top 10 as well.
(2) Rossi's health uncertainty. I want to see Rossi actually play this year and see his progression, before declaring him back. He may have some rust in his game that needs to be knocked off, but given the top 5 slots for Minnesota being 3rd isn't that bad.
(3) There is a razor thin margin between all four prospects for Minnesota; Boldy, Rossi, Wallstedt and Lambos are all blue chip guys that could become elite players for Minnesota in the future. Boldy is the most ready and that's why I think he's number 1. Wallstedt, Rossi and Lambos are all the next up. Wallstedt is higher, because of his record breaking career. I didn't even think he would be available at 10, less 20.
(4) Position of important; yes, you need a top center. But you also need a top goaltender. We all saw how valuable goaltending was in the playoffs this year. Minnesota has never had a top flight goaltender in their draft year. Harding, Hackett, Jones, Kuemper, Lindberg, Kahkonen were good goaltenders, but they weren't considered blue chip or elite guys. Most of them were seen as platooned goaltenders. Wallstedt is the first goaltender Minnesota has taken that had elite potential right off the bat. So I'm a little biased there.