Is there a comprehensive list of what is available, weapons/systems/avionics/feature etc-wise currently in this sim? I search around I see mention of things here and there, but never a full current list.

For instance, is the Helmet Cueing System operational? The knob works, but nothing happens...and I don't see it mentioned one way or another anywhere...

v6,
boNes

There's a thread in the DCS forums. If you ask over there they should be able to point you in the right direction.