So you're trading an ascending 2nd-3rd tier quarterback who's created a good rapport with one of the best receivers in the league (not to mention a second round player with promise) and replacing him with an immobile player that has not established himself as a proven starter in this league. In doing so, you've narrowed your offensive diversity because Rosen is not a running threat and isn't nearly as likely to escape the pass rush.
In exchange, you're saving cap space and the ability to draft a couple of players that you aren't sure will ever be productive, much less superior to the players you have now.
At the most important position for every team in the league. Hmm.....
Presuming your interest in the trade is born of the notion that you'd like your preferred team to be more successful in the real world, let me suggest that discounting the psychological impact of replacing a well-liked employee in the top leadership position of your organization is foolish..... hypothetically speaking.