well as i said before I don't think there's any rule or any law, and i guess it all depends on the song self. In my case my show is a bit of storytelling and it's atmospheric itself, so we do enhance with effects to bring the mood, drawn lady, watery synths, equalization effects... that kind of stuff. And about the stage we enhance the effects with accoustic effects for example, whistling on flute for winds, or spinning a windband or digeridoos, actually it's funny. Guess it wouldn't work maybe for some genres but it works really well on others.
I guess in some songs they could be annoying and drive attention away, but yet again we must see if they go along with the concept of the song self and how it works specifically in the track in question. We have all sorts of accoustic things to enchance the fx then on stage, you can use from synths, to theremins, to rare percussion staff.
recommendation. have you heard of "WATERPHONES" , it's an instrument that's used in soundtracks, make the weirdest coolest sounds ever smile

Priscilla Hernandez singer-songwriter
http://www.yidneth.com
New album at:
http://theunderliving.com