Murray is a much better prospect than Rosen. And I think Rosen is a good prospect. Rosen was drafted in a fair stop and has value for sure.
Murray though is a better and more consistent passer in the pocket. Murray is one of the best Qbs by throws in the pocket in college the last five years. And can run. QB runs are a one of the most valuable types of plays in football. Especially behind that Cards line.
If Im the Cards I happily pick Murray and trade Rosen when a team offers a first rounder. Murray is that shiny new thing but he is hella good.