If you take Longenhagen's comps at face value, Ramirez's ceiling is roughly as a 2-4 WAR super utility type whose primary value is going to come from his contact ability with some pop. That's a pretty good profile to have, and it's something that should age reasonably well. I think you can make a case for him being the #1 prospect in this system currently.
My problem is, I just don't see where he (or Rojas, for that matter) fits on this roster over the next two years. I don't think any of Shaw/Rojas/Ramirez have the sort of bat that would justify taking over full time in a corner OF spot, and I also don't think either Rojas or Ramirez would be an improvement over Shaw over the next two years in a super utility role.
Injuries Happen and Baseball Is Dumb, and it's a really good conundrum for the Cubs to have, but I'm seeing both of them as high quality trade bait at the deadline or in the post-lockout offseason.