Personally, I can't see a need for a Start Menu in Windows RT, however there is one thing I think is a shame. In Windows 8, using a mouse or trackpad (and this does work in RT) if you right click on the Start thumbnail that pops up in the bottom left on the desktop, you get a context menu that gives you links to loads of useful stuff like cmd, Run, Control Panel, System Properties and loads of other stuff. There doesn't seem to be a way to access this using touch though. Hold down and release in the corner doesn't work because you cant get the thumbnail up in the first place - I think. So you have to go through All Apps from the Start Screen to get to these utilities.
It would be nice if it were possible to access this context menu somehow.