Keep in mind that moving Merling out to SOLB could only be the safety net that allows us to fix the position by drafting only one guy instead of acquiring multiple players. We all know how this regime likes to fix holes by double-picking.
As Simon points out, if you move Merling, then grabbing a Jason Pierre-Paul at #12 and counting on him to help fix the defense would not be such a big gamble. We gambled on Sean Smith and Vontae Davis to fix the secondary and replace Andre Goodman. They did about as well as they could as rookies and yet the secondary was still a huge problem. I don't think you want that at any position, you need good options.
Another thing about moving Merling is, it allows you to keep flipping rocks at the DE position which they consider to be quite possibly the most important on the defense. Personnel is a percentage game. If you roll the dice X number of times, chances are if you're doing your job, you'll win Y number of times. The only way to guarantee you don't win is if you don't roll the dice. Phil Merling took 376 snaps this year along the DL where we could potentially be dishing those snaps out to some guys like Lionel Dotson, Ryan Baker, and some new guys who are begging to get on the field so that they can show us whether they're the next Jay Ratliff or not.
In a way, Phil Merling and Tony McDaniel are extremely solid rotators that help you win games. But in another way, they're drain stoppers that keep you from discovering the next big thing. It might be wise to clear one of those drain stoppers while keeping the other in place...so that you can keep searching for the next star.