why wipe out the hard drive, tho? You can usually just switch DEs just fine, this isn't windows :) long gone are the days where we would have 10 different DEs/WMs installed
You can certainly remove packages that were installed as dependencies, even if `apt remove` doesn't do this by default. I think it's `apt autoremove` or `apt purge` (although I haven't used apt in a long time). All of the package managers I've used have a way to do this.
On the other hand, for the average user I don't know why you'd bother. It's not like it's interfering with other stuff you want to do, unless you are extremely tight on hard drive space.
If you have the time to debug these and straighten them out, it's fine, but given how simple a clean install is these days that's often the easier path.