"I think at the very least we can agree that it is the employee's job to inform their superiors of feature creep, looming technical debt, and whatever bad practices they see. "

Yes, please yes. This is really where 1-1s come into their own. I can ask directly - is there any part of the code you're working on that truly sucks, and is going to break? I don't care who wrote it or when (it was probably me), I just need to know, so I can put it in the backlog