The value of debian is not that they package (or repackage) everything into deb files but that they resolve versioning and dependancy conflicts, slip security fixes into old versions of libraries (when newer version break API/ABI), and make it possible to integrate completely disparate software into a system. They also have a great track record at it.
Maven does not do any of these things; Maven does nothing to protect the system administrator from a stupid developer, it just makes it easier for their code to breed and fester.
You must understand that the sysadmin has an enormous responsibility that is difficult for programmers to fully appreciate: You don't feel responsible for your bugs, you don't feel responsible for mistakes made by the developer of a library you use, and you certainly don't feel responsible for the behaviour of some other program on the same machine as your software, after all: Your program is sufficiently modular and scalable and even if it isn't, programming is hard, and every software has bugs.
But the sysadmin does feel responsible. He is responsible for the decisions you make, so if you seem to be making decisions that help him (like making it easy for you to get your software into debian) then he finds it easier to trust you. If you make him play whackamole with dependencies, and require a server (or a container) all to yourself, and don't document how to deal with your logfiles (or even where they show up), how or when you will communicate with remote hosts, how much bandwidth you'll use, and so on: That's what Maven is. It's a surprise box that encourages shotgun debugging and using ausearch features to do upgrades. Maven is a programmer-decision that causes a lot of sysadmins grief a few months to a few years after deployment, so it shouldn't surprise you to find that the seasoned sysadmin is hostile to it.