Great points to bring up about placement of switches.
All of my power/Ign switches are grouped to the far left and the ignition switches are fitted with guards.
Once the aircraft is started,my hands have no need to visit this location until shut down thereby reducing the possibility of accidentally turning off critical systems.
The Dual CPI is about as independent as you can get with an EI. They do not share any common Power or Earths and only share the same physical location for the Dual Crank sensor. ( a sensor that is well protected,see earlier in this post )
However I agree that this design requires a robust electrical design and simple is nearly always better. Both ignitions are protected from over-voltage and the aux battery is monitored by the Dynon's.
It was interesting walking the flight-line at Oshkosh when I was last there and there was a Carbon Cub with the cowls off. It was fitted with Dual Lighspeed ignition and the crank sensor wires were just hanging in the breeze unprotected and un-clamped. Some people just don't understand what a robust wiring install looks like!
The benefits of EI are well documented and as has been pointed out many times a correctly timed and operated Mag System below 8000 ft is very similar in performance to any EI.
Having Dual Fuel Maps for the different fuels is a huge benefit to me.
My aircraft was approaching 500 hrs so , money had to be spent anyway servicing the mags.
The gains to be had are in cost of ownership over time and the fuel savings up high if you are a long distance cruiser. The spark energy is nearly 7 times greater with any EI and enhances all modes of operation especially hot starts and aggressive leaning at idle,no more fouled plugs.
The early adopters to this tech have paved the way for more attractive packages to be offered by SDS and others.