The biggest hurdle with Glenn is he worked for the Saints already and knows exactly how Loomis screws up a roster with his management style. He may not want to work for that!
Loomis' hesitance to move on from this particular style of cap management is on him and we'll see what direction the FO as a whole goes in with regards to that after we get our HC and Staff in place.
Thing is, Loomis got himself in this position by trusting his good friend and the best HC in Saints history Sean Payton's opinion on how to build the roster out, and largely they chose veterans and rookies they drafted higher over developmental guys who flashed late in their time here. They obviously started the idea to maximize the window while Brees was still around and if not for some really inopportune screw ups both offensively and defensively, or the worst blown call in NFL history, would have resulted in at least one more trip to the Super Bowl. The FO expected Sean Payton to stick around post-Brees, especially with all the "Our next QB is in the building" talk. In hindsight it obviously should've been abandoned once Payton decided to step away which again is on Loomis but, in my opinion anyway, I think it shows a willingness to defer to the HC and Coaching staff more than a lot of other GMs and even owners do. I say all this to make the point that what some of us here see as a problem regarding Loomis the other perspective is that he's ultimately going to let the football guys make the football decisions and manage the cap accordingly and some coaches would find that very attractive, particularly if they're "guaranteed" a level of job security whilst the situation resolves itself.
Now if the next guy comes in and wants to tear it down and Loomis outright refuses well that's a wholly different story. In Loomis mind the DA hire was so they didn't have to tear it down, unfortunately for all of us DA just wasn't that guy.