Sounds like you might be biased to medium focal length images
Or maybe it's because of all the Hubble Photos
What sort of mount do you have? Must be pretty beefy to handle a 12" newt. The only drawbacks I've experienced are fairly minor. Colimation every time you move it, the length compared to collapsed reflector style telescopes, diffraction spikes and the awkward focuser position. I also have experienced my secondary getting dewed up but that seems to be pretty rare, seems like if I were to add heating it might disrupt the view with all the thermal air currents but I'll have to do more research.