create polygon tool

thinking there should be a tool, to allow the user to just draw out polygons.

both maya and silo have this tool, which works simply just by clicking where you want verts with a preview of the polygon as you draw and pressing q or enter to drop the tool and finalize the result.

and as far as position, having the new verts draw onto the grid or workplane would work great.

Did you tried "rotopo" tool?
It's pretty much beefed up poly create tool, which has features from XSI and Silo, only difference is that it operates,or feels as a totally separate feature, I'm not sure if Istonia could integrate it without it feeling disconnected from the rest of the tools.
it is powerful and quick though. Works with snapping. 

http://voidworld.cmcproductions.co.uk/index.php/topic,176.0.html