I remember from my professional time many good reasons for the root user to be set up to boot into a text mode.  I do not remember any good reasons for root to be prevented from using GUI applications (even though xterm was the one most used then).  
<br><br>1) Can anyone tell me why distros prevent root from using GUI applications (e.g. display not defined)?<br><br>I seem to remember each user having a runlevel defined.&nbsp; That was primarily (I think) because everyone ran a workstation terminal so the runlevel was local.&nbsp; But I also remember the SA coming to my desk and logging in to a system prompt and if he wanted xterms he had to startx first whereas when I logged in as me the GUI was automatic without me having to startx manually.
<br><br>2) Can I set up ubuntu like that and so root could startx and run GUI apps if I wanted instead of having to sudo them from my user?<br clear="all"><br>-- <br>Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.&nbsp;&nbsp;- Dr. Seuss