The official answer to multi-user is not "no", it's "not yet".
I'm not too fond of the UNIX-style admin/user separation, however. xkcd explains this better than I can: https://xkcd.com/1200/
I would rather get inspiration from what Android tries to do: no root access, applications get fine-grained permissions when they need them (to access your webcam, deal with your files, etc), either at installation time or when they first request them. This brings real value in protecting the user data and privacy, much better than a separate root account would. It is also somewhat orthogonal to multi-user support.