Yeah, I thought about this before posting & the only logical point that popped into my mind at the time is that Holden no longer has the engineering base for the Vectra to work from, especially in facelift guise. The Astra VXR is here, in part, because the base Astra's are here therefor, the engineering base is in place. Same could be said for the Vectra as we have had the C model but we haven't/don't have the facelift C which does have some significant changes to pre facelift. There may have been enough significant changes for Holden to think, st*ff this? However, HSV is a different beast so who knows. The new boss may just have the kahuna's to want to bring the VXR Vectra in.
Maybe if we all keep our fingers crossed for longer enough we may see the D model..........................