@jtauber @cpennington 

Can I get specific feedback here?

While I'd like to have a simple means for developers to run 'preview' and 'published' LMS in the same localdev instance. This particular change will require all devs - including open source people - to have to define a 'preview.localhost" in their local HOSTS file. I'm concerned that outside people will get latest and then complain they get an error when clicking 'Preview' from CMS.

I can remove this change and make yet a new envs .py file (say, dev-edx.py) that we just use internally. Or again, I can just remove this and do nothing else...