That’s essentially what I said, it works 90% of the time. That’s the most stable it’s ever been. Having the EQ numbers match on the S3 is a huge improvement. They DO NOT MATCH on the Artist Series. I was more than willing to go for an S3. But I need more than 16 faders and they wouldn’t give them the linking feature that EVERY OTHER CONTROLLER in their lineup and all of their competition offers! Clearly, this was meant to force you to buy an S6. That’s the only reason they could possibly have for omitting it! 
So, as I said, I’m limping along with Artist Series.
Here’s the thing. As I understand it. Eucon is essentially MIDI on Cat 5/6 cable, which is what offers the extra band with for all of the deep integration. Nuage has THEIR VERSION and Smart AV had THEIR VERSION. Why won’t Yamaha just give us THEIR VERSION? It’s still MIDI. Just call it Super MIDI or “Spark” or whatever marketing comes up with. Nobody cares what you call it, as long as it works.
You’re right about the Mackie/MCU protocol. That with Metagrid or X-Keys would definitely get you pretty close. That’s why I was considering the Qcon Pro X for so long. I could get 25 faders and it follows EVERY MOVE Cubase made on screen! But you’re limited to programming only the F keys, which puts all of the programming onto other devices for the Key Commands. Now you’ve got a serious ergonomic problem. Where do you put those other ESSENTIAL devices within easy reach and view without getting in the way of the “Official” Controller?
That’s what so vexing. It CAN be done and almost everybody is doing SOME piece of it (Avid, Behringer, Mackie, Neve, Peavey, Presonus, Smart AV, SoftTube, SSL, Tascam, WK, Yamaha and on and on)! I don’t understand why SB is leaving this giant hole in the market with SO MANY POTENTIAL CUSTOMERS LITERALLY BEGGING THEM DAILY for a solution!