Ah, but there are measurements which reveal the condition of concern. If there is no measured lobing/comb filtering/phase issues at a certain listening location, then the negative effects on imaging and soundstage should be non-existent. Again, you said there are negative affects on imaging and soundstage due to lobing. If there is no lobing at a given listening location then it follows that there is no effect on imaging and soundstage. I agree that there is no way to get rid of some degree of lobing with stacked speakers. However, that does not mean that lobing is necessarily evident in all listening positions. On your main contention I will agree to disagree. Thanks.
Emotiva ERC-1, USP-1 & two UPA-1s
Pro-Ject Xpression III & AT440MLa
AKAI AT-2600 & Harman Kardon TD4400
Magnepan MMG Magnestands
Rythmik Audio F12