I have to disagree.. Separation comes from each musician knowing where their instrument fits in the sonic landscape and adjusting the tone/timbre of their gear accordingly. THIS is a rarity in my experience.
In the average room one doesn't need reverb (unless for a special effect) on bass or guitar amps. If needed in a really small room, FOH can add a bit. In a hotel ballroom or large room.. there is NO need for it, but I get fed it all the time! Dynamics are the ebb and flow of the song! Still necessary, but dynamics are not going to fix a crappy stage sound.
THIS I DO agree with +100%. Experienced musicians KNOW this and know where they fit. Keys don't stomp on bass. Bass doesn't punch LF to muffle the kick, and the FOH guy knows how to make the best of GOOD signals s/he's being fed!