Again, being a Michigan student, I have a massive hard-on for Trouba, and I wouldn't mind seeing Gabby traded 1 for 1 for Trouba. I'm always the guy who prefers his proven players over potential (i.e. I was someone arguing that Kreider would not just slide in and fill Dubinsky's role right off the bat), but I really think he's going to be the next big thing at the NHL level.
If we can manage to get Trouba at the NHL level, I'd be more than willing to swap Girardi (considering his age, the way his body will soon disintegrate from the abuse it takes, and the fact that I think the majority of us on this board have a better breakout pass than he does) for a 2nd line young center (think a ROR type)
2013-14 (and beyond) roster
Hagelin-Stepan-Nash
Kreider-ROR-Fast
Fast-Miller-Callahan
Powe-Boyle/Noob-Asham/Heavyweight (Sather always signs his goons) (In reality though, a fourth line is pretty interchangeable. Two years from now, it's likely we'll have 3 different fourth liners)
That third line LW can be filled by someone like Hrvik, Thomas, or any stopgap or prospect that surprises us and surpasses expectations.
Staal-DZ
McD-Trouba
Stralman (Skjei in one-two years time)-McIlrath
This is a D we could have set in stone for eight-ten more years.
Same first line we all know and love (depends on the day I guess..), very good second line if Kreider develops the way we want him to, very hard-working and defensively responsible (with lots of offensive talent to boot) third line, with a very good well-rounded D and the best goalie in the game.