Its an interesting point. You'll see a lot of folks out there touting that he 'was only 20' and will expect even higher offensive output. With his BABIP, it just isn't possible. The concept of 'regression to the mean' applies to all baseball players equally, no matter how awesome they are.
To put the financials in context:
-The league average salary is 90.000m, with 25.000m cap space.
-Post trade, Team 1 would have a salary of 86.200m, with 28.800m cap space.
-Post trade, Team 2 would have a salary of 68.000m, with 47.000m cap space.
Top Free Agents, Batters: Cano, Teixeira, Rios, Crawford, Cruz N., Suzuki, Howard, Konerko, Jeter, Gardner
Top Free Agents, Pitchers: Kershaw, Peavy, Rodney, Estrada, Pettitte, Rivera, Lohse, Hammel, McDonald
Give me team 2. Team 1 is getting some solid player outside of Trout but nothing I would consider great. As for Trout, I am one of the skeptics. I have seen too many rookies take a step back the second year and I wouldn't be surprised if Trout falls back further than people think. His numbers last year were historic and unlikely to be repeated and then add some regression to that and I won't be investing in him this year.
Team 2 is full of guys that you are pretty sure you know what they are going to get and most of it is really good and Strasburg could easily be great this year. Love getting Dunn over Smoak, tough losing Walker but Westmoreland is solid.
The only thing I am not adding to the equation is the salary. Too different of a pay system to really be able to understand what the values are and then way too much going on in the trade as well.