Glider cases don't mount the gear as secure and some of us don't need 3 foot wide controllers. The Denon was a perfect size and had almost all the functionality a basic mobile DJ would need. Yes, not for someone who needed the larger tactile controls, but it was popular for a reason.
Because the rest of my gear is standard rack mount, it make for a more compact system with less total pieces to transport and connect together
That is super limiting. You would be better of with one small 4 RU rack to put all the other rack stuff in. Yes, it's one more piece, but it allows much more flexibility and freedom in the future.
What do you have that is rackmount anyhow?
Mic receiver, lighting controller, DSP??
You can argue it is not as secure, but it's not not secure. I have never heard of anyone, and speaking from experience have an issue with their gear b/c it's not screwed in. The cases are custom fit for the equipment.