I’m not sure what’s up with their roadmap (ha!), but with SU13 they did update SimConnect with new features regarding “Input Events” (basically “B” vars). I’ve been playing with them (for the TP plugin I maintain). It’s a… nice, or at least interesting, start, for sure.
The good news is that I’ve been able to successfully set/activate an input event with a value. This is equivalent to, for example, using Dev Mode Tools → Behaviors → Input Events → Pinned → Execute with a Parameter on a “_Set” event. Eg:
(from https://devsupport.flightsimulator.com/t/behaviourdebug-inputevents-currently-tracked-values-extra-set-event-showing-after-simconnect-setinputevent-call/6580)
The unfortunate part is that it’s not ready for prime-time at all yet. Besides the implementation itself being kinda strange (awkward to use and not really following established SimConnect precedents), it’s also just plain buggy. For examples:
- https://devsupport.flightsimulator.com/search?q=input%20event%20%23bug-reports%20order%3Alatest
- https://devsupport.flightsimulator.com/search?q=enumerateinputevents%20%23questions%20order%3Alatest
I can also get/read the current input event values, but it’s extremely volatile in terms of crashing the sim.
But yea, it’s some kinda progress! 
Cheers,
-Max