The organization and the culture
Why would you prefer him not be the GM?
For some of the reasons you already discussed. He trades up too often, doesn't value draft picks enough, signs older players to deals with void years that lock you into those players past when you might want to let them go, and drafts have been mediocre.
Maybe he can turn those things around, but my preference would be to have a new GM with talent evaluation skills and a fresh perspective on things. Plus, Loomis is 68. Most people that age are usually pretty set in their ways and it's difficult for them to accept new ideas and new ways to do things.
I just don't feel the need to call Loomis a loser and list all the reasons he sucks in every post I make.
Edit: Oh and I think he started this rebuild about 3 years too late, kept DA 1 1/2 years too long, should not have signed Carr, and is now moving a bit too slow in the rebuild. But, at least he traded Lattimore and showed some restraint in free agency for the last few years outside of singing Carr.