>> So, do you think adding a warning about symlink
>> handling issues in the docs would be enough?
> Given the constraints, yes, it would be good to have that warning in
> the docs.

Okay.  Adding the easy keyword to lure contributors.

> Even better would be a runtime hint like

I’m not a fan of the idea.  You have to keep warnings few if you want people to heed them.

>> For distutils2 however, compatibility concerns do not apply yet,
>> so we’re free to fix and document symlink handling.

Thinking again about that, I wonder if there is something to fix at all; tar is a smart container format whereas zip is simpler, so I would not be surprised if the 
source of the difference is just that zip cannot contain links.