It’s looking like fluidIA is becoming reliant on keypressing and keyholding. This is in order to speed up the interaction of prototype creation. Keypressing however comes with the burden of having a higher learning curve. In order to decrease this learning curve, here are some very quick and rough ideas on how to make keypressing combined with mouse interactions a little bit easier.
Dear Jakub, as a matter of fact, a keyboard driven interface is a perfectly good idea for the high performance, regular user. And I have the impression that your interface is meant for this type of user. Probably a good model is Blender, that is a nightmare for the newcomer and a dream for the regular – I personally like the "mouse in one hand, other hand on the keyboard" paradigm, it is enormously faster than picking options from popups.
Walter, I also intuitively feel that the mouse + keyboard combination will be quicker than the mouse on its own, and easier than pure keyboard commands. Would there be some sort of academic literature to support this? I guess by Blender you meant this application: http://www.gamedev.net/reference/art/features/ble... ?