No. All you need is a Raspberry Pi (preferably a 2) with Linux (plus monitor or TV and keyboard, mouse) and that is _all_ you need. The Pi is perfectly adequate as a development machine. It can even run Arduino development.
Very good point. This is how I have mine old RPi1 set up. I even have my toy OpenGL ES 2.0 apps building on it and running on the console without X. When I am running X I tend to prefer older window managers like WindowMaker, the old ones seem to play nicer with poorly accelerated X servers.
$35 computer + $30 64GB SD + $150 22" LCD + $95 mechanical keyboard + $30 mouse