I agree on the compelling nature of the SV picture, but system integrity and accuracy needs to be addressed in certification, so the SV, in service, can be relied on or it is removed and pilot alerted of its degradation. Yes, an erroneous SV picture would be very difficult to discern in any IMC case.
Your comment on putting the "primary objects of interest in the center of display" does make the flight path-centric cueing more sensible. To put an extreme example, with track-centric cue, one could fly an ILS inverted and the FD cue would be perfect. Or, more reasonably, the FD cue and FPV centered with some rather large pitch/roll excursions that wouldn't be as noticeable as when flying the attitude reference. For example, you are slightly off course, with flight path cueing, you roll to establish a new heading but the roll angle isn't seen by having only the cue in limited view and over bank. On raw data or attitude orientation, one might roll 5 degrees to make a 5 degree course change.
Last edited by galaxy flyer; 9th Feb 2017 at 21:16.