Over on VAF, someone is asking for the heading tape on SkyView and to get rid of the HSI on the PFD!
We didn't avoid doing it on the PFD for lack of time reasons. We actually had it coded up once back in about 2004. We didn't do it because it's really, really confusing on a D10A sized screen, with numbers all over the place, digits rotating and spinning. Given that we put CDI/GS needles, course pointers, and ground track pointers all on the screen already, you really get 95% of the function without those issues.
SkyVew was designed ground up to have it on the screen under the PFD, which is really where it should be if it's on the PFD. To do this on the D100 would require a total screen layout change.