Another thing to consider: most of the newer rigs include ducker delay - meaning the degree of delay is dependent on the picking attack itself. The same can be done for distortion so it will go from very heavy saturated gain to a more slightly dirty sound for ore restrained picking. Everything you hear on a studio recording though is added after the guitar parts are recorded in post effects treatment and quite often involves adding combinations of VST plug ins or routing the signal through something like an Eventide rack unit.
A good delay sound though has a lot to do with synchronising the feedback tempo with the bpm of the track so that everything is in time.