Hi Jeremy,
Like yourself, I've been at this a long time, on a professional level (it's all I do to support my family), some with real orchestra, some with samples, so I'm very used to the difference. And my point that William decided to make fun of was that I'm old enough to have started before all the sampling stuff really got going. In the beginning down here in Florida I did nothing but live sessions with live strings, woodwinds, etc, for TV and radio. I jumped on sampling as soon as I could afford it, with Emulators, etc, all the way up to now with VSL and LASS, etc, etc.
And again, I think it's great that we have these tools. Not every client has the budget for live musicians, hardly any anymore where I am, save for Sandals Resorts whose commercials I do and use real strings almost on every spot. And I certainly agree with you about having to write "around" samples. It becomes less restrictive it seems all the time, but there are still many things you have to watch, and many mixing tricks to enhance what realism you get from the various libraries. I do it daily so I know what you mean.
I do believe that if it were possible to play a large orchestral piece side by side with any sampled version, it would still, here in 2011, be fairly obvious which one sounded superior.
I'm not sure "fooling the listener" should be the litmus test...most listeners couldn't tell whether we recorded a master with proper levels or quality gear either, in that they listen on mp3 players, but WE hear the difference. Jerry Goldsmith once said "Don't ever kid yourself that you are not making music for yourself" and I couldn't agree more...we have to be happy...first.
If there are many among you who, given the choice of using a roomful of excellent live players and a sample library, would choose the library, that's super and more power to you. I would not have think about which I would choose for a nanosecond.
TH