Time will tell. Might be a good trade, might be a bad one. Two 2nd rounders and a 3rd for a guy with only 28 career starts whom you are expecting to be your #1 goalie is a bit of a gamble.
Teams do this all the time. You never really know what a goalie is capable of until you see them put a long string of NHL starts together.
Sometimes you get Bryzgalov, sometimes you get Roman Turek. This is more than the established price for a backup that you're hoping will be your starter - historically those guys have brought single 2nd round picks. But in this case, Tampa has such a huge hole in net and they have some extra picks from the deadline, so they have more flexibility than most teams.
He does seem to work magic. Him and Trotz and my two favorite coaches.
Tippett got too friendly with the veterans during his time in Dallas. He completely allowed the country club atmosphere to take hold. And his veterans, despite how they were playing, could do no wrong... meanwhile you had James Neal and Jamie Benn knocking at the door. He also rode his goalie, Turco, into the ground each season so by playoffs the guy was gassed. And don't get me started on Tippett trying to sit on a 1 goal lead for half the game. Boring hockey to watch and furthermore it bit them in the ass dozens of time. The powerplay was always a sore spot, too.
Now all of that being said, I think he learned A LOT from those mistakes. He seems to has fixed most of them in Phoenix.