When you speak of the imaging of spaced omnis, you need to specify what their spacing was; the stereo image they produce is entirely based on the distance between them.
A spacing that combines fairly accurate imaging with a euphonic 'bloom' is right around two feet (Tony Faulkner uses 26-27"); as you get any wider than that the middle becomes weaker and weaker till you get just two 'pools' of sound around the left and right speakers with little happening in the center.
Here is an excellent online tool for graphically displaying the approximate image width produced by various stereo pairs:
https://sengpielaudio.com/Visualization-AB60-E.htm
You'll find that the main arrays used by most of the major labels during the heyday of the Classical record business did not produce technically accurate stereo imaging; rather they produced a pleasing, engaging and 'plausible' stereo image. Only a couple of 'boutique' labels used coincident mics for the main pickup. Aubort referred to coincident techniques as "fat mono".