FWIW, my concept of a lav mic on the musician was to reintroduce some of the normal stimulus they would get if their ears weren't plugged, thereby hopefully removing some occsaional early-adoption objections to 'it just doesn't feel right' (I am working with a guy this weekend whose entire band is on IEMS,except him). The musicians would still have the benefits of isolation, stage volume control, and detailed mix control of IEMS, but they would also be able to dial in some of the 'pre-IEM' sound.
Yes, I completely see your point, and I think its a good one.
I didn't mean to suggest that a front of stage pair was the only way, just that a simple approach is normally best and that there is no substitute for starting with a great IEM mix before ambience that captures all the elements of the performance that the artist wants to hear.
But your point about transitioning is a good one.
If you are a musician, and play in a band very regularly or full-time, you are almost certainly doing yourself permanent hearing damage without using in-ears (you may still be with them, but at least the dosage is in your control a bit more). This isn't because everyone has >100dBA stages, but that the risk of hearing damage in our industry is almost entirely caused by long dosages of moderately loud noise (>85dBA, <100dBA), rather than short-term exposure to really loud (>115dBA) sounds.
So getting people onto IEMs is a good idea all round.
I think IEMs with an ambient vent are great, although you want to be able to plug this at a later date if you'd like. The active-ambience systems like the Sensaphonics and ACS systems are ideal, but come at a cost.
That being said, I also think that its near-impossible to expect a full band to have a great IEM experience without either a personal mixing system of some kind, or a monitor engineer. Wedges are quite forgiving, whereas IEMs aren't