Can you just put all the Vuze UI code into a separate file?
Technically, yes. However, that means that whenever we want to send out updates, you have the potential for breaking the interface. The Vuze UI needs to be kept in sync with the Azureus core code itself – and if they get out of sync, you’ll end up with a broken interface (which you might not be able to resolve without installing). That’s the same reason why we don’t (and wouldn’t) distribute the classic user interface separately.