I'm not sure the detached HEAD state would be more confusing to inexperienced engineers. If they are only using arc, they will never need to know. If they accidentally commit to master the inexperienced engineers later run into problems as described by @cspeckmim in https://secure.phabricator.com/T9082#130289. So both detached HEAD and finishing on master could be confusing for inexperienced engineers.

Simply put, I don't see the purpose of master as a branch if you never commit to it. It's just clutter and an implementation detail of arcanist.

@epriestley I very much doubt most users of phabricator have that many branches. Personally, I restrict my branches to code I plan to work on in the ~1 month time scale. The rest I create differential revisions for and then delete locally. I can arc patch them back in later. I would say the fact that git branch is useless for you is probably an indication that you aren't using branches in the expected manner.