I don´t agree with you. Metal Rock and many people use two amps and my sound is also composed of two different amplifiers.
To use 2 amplifiers have to know how to use it to join, if you do not know how to do it is better to wear one.
... and I agree with you too, JH-2.
The thing is, I wasn't talking about your style of music. If you've got bass, strings, brass, synthesisers, piano and / or electric piano, percussion, vocal harmonies, clean and dirty guitar parts etc. all in your mix, dual-amp tones, with all those extra harmonics (frequencies) to contend with, make it trickier to fit these guitar parts into it.
This is quite different from the sort of thing you're talking about. If it's (just) drums, bass, vocals and maybe one other guitar, it's a "Helluvanother " ball game IMHO.