Let's take an example of the famous NFS game. When I play it I would rather need a large angle of tilt to move around, a real game addict would move the game pad left to negitiate a super sharp left corner; it does not provide more left turn effect but it gives you the maximum concentration to one side. A turning chair is thus necessary.
It is also ideal for a gaming chair to be tall enough, to raise you to almost the same level to the screen; I like putting screen on the wall, like 2m high to avoid any passing guy from messing around my screen view.
The chair should also be soft. Comfort is the master of it all.
