I think everyone understands that software is a key piece of voice recognition.
If you would read the posts, to me it is very very clear that there is an issue between the mic and its associated decoding (analog circuit - hardware).
If you have a VERY noisy circuit (regardless of where that noise comes from), you would need very good noise cancellation circuitry/SW to clear that up (similar to what the Jawbones of the world do). Taking an analog mic input, and converting it is nothing more than trivial. This is the garbage-in portion of my garbage in = garbage out analogy.
VR is also trivial - you buy a SW module that runs on the WinCE OS. However, if you feed that module a noisy input, the VR software will not perform (hence the garbage out portion of the garbage in = garbage out analogy).
Try driving in a Lexus with the sunroof open, and windows down - make a phone call - the caller will hear noise. Now try using VR in the same system - guess what - it's not going to perform well... Strange things happen when you will a signal with noise.........
As for the Z130 working, unless they changed the analog circuit (via different components, or PCB layout), it likely has the same issue(s)... I haven't seen enough here to show me anything has changed from the Z110/Z120. I'd guess very little has changed - and it would take more than one or two posts to convince me otherwise. You don't think Pioneer posts here too 
If you have the time and knowledge, you could trace the schematic - find the analog input to its amplifier - cut traces, hard wire a mic onto the PCB. If you still get noise, you could build your own mic/amp with a nice filter, shielded cable and quality components - then cut out the old, and solder in the new (as close to the ARM input - if indeed that's the chip doing the AD - as possible)...............
Or as I have done, give up using BT for calls, and chalk it up to features that suck (BT calls, VR)...
You won't fix it with a mic or software... And yes they have released at least 3 versions of BT software - if you think there's a bug in the code introducing this background noise, surely that would have been fixed long ago (in Z120 - yes Z120 had like 2 BT updates)...
Soon hopefully the system will open up and at least give us a few things to play with...