What's your opinion on processing the Nion's command response when using a Crestron controller? Is it worth the bother to process the response in the Crestron to ensure true feedback or do you accept it on faith that the control transmission works every time?

I like true feedback, but there are MANY projects that use the faith method.
It is up to you how you want to program the control system.
Fergy

Blind faith is never a good idea (unless you're into Clapton), but if you build solid reference points into the programming it's less of a problem.
Some options: when control system connects do cg on everything, or when user opens a page do cgg on the relevant controls.