Marc,
Good question.
Space Syntax? How many developers? I think there is only one guy coding Kangaroo: Daniel Piker. And he isn't a full time coder. Probably all based on some open source physics engine from the gaming world.
Please note that ole Robert Cervelione already has a GC version of Kangaroo.
Easy-peasy for all those agile pro-coders in India, right?
Generalised rules engine? Does Bentley have one anymore? Do you mean D++? I doubt a rules engine will be fast enough.
Regards
Dominic