I think if one looked at the generic possibilities of a "good" FADEC system it would go something like this:

Hp  - There should be significant improvements based on optimizing thetaPP.  This would suggest a measurable improvement at takeoff power as well as during cruise as compared to the compromised deficiencies of a fixed timing system.

BSFC  - There should be a slight improvement across the entire mixture sweep, but the most noticeable improvement would be when at BSFC(min) and leaner.  I currently operate at BSFC(min) as a matter of routine.

CHT  - Dramatic improvements in CHT control should be the result of ICP control.

Price  - Should be reasonably competitive with the cost of a pair mags over a TBO run.

TBO  - Improved TBOs as a result of controlling ICPs.  (This would not improve the life of valves, which is dependent on fit and manufacturing techniques much more so than operating technique.)

Weight  - Should not be much heavier than mags.  This suggests minimal wiring, CPUs, and a minimal number of connectors.

F:A ratios - Should remain balanced during all mixture combinations and all power settings at all times.

Maintenance - It should be field-friendly, having good dispatchablilty with partial system failure.  If the electronics should fail, it should revert to acting like a mag.

A good FADEC/electronic ignition would allow me to operate at very high powers, with controlled peak internal cylinder pressures and controlled CHTs.  This would suggest that it should be able to operate LOP at high cruise power settings where BMEP is high and Peak Pressures are low.  It also requires that the pilot have control over the operating parameters to allow for mission specific requirements.  This is one case where one size does not fit all.  I routinely operate a TNIO-550 at 85-90% power (255-270HP) in cruise burning between 17 and 18 gph for a BSFC of .388.  I do not want to slow down, have a higher BSFC, or burn more fuel to have a FADEC system.  That would be a step backwards from how I'm currently operating.

The first system to address all of the above issues will get my business and will likely be quite successful.  Short of fulfilling all of those requirements, any system is fighting an up-hill battle in the real world.  I have my eye on the system that does address all of these concerns.

Walter