If so, did they ever get a chance to practice takeoffs in that configuration in a simulator environment (say in I/T/U or recurrent training), or were they simply given an edict to start doing it that way?
I'm not saying that the takeoff configuration is inherently unsafe. I believe it has advantages and disadvantages. It would be nice to have it as a selectable option based on the particuar circumstances of weather, weight, runway, and terrain considerations. As it is, we have no choice, we had no warning, and most pilots have only performed takeoffs with that configuration very rarely, if ever. Some Captains might even evaluate a takeoff with that configuration as one of those circumstances where he should, per FOM advice, perform the takeoff instead of the FO.
As MaydayMark mentioned, they did the same thing with the MD-11. New procedure, no training, just an edict. No tailscrapes to date, but we've had freight bumped because of discomfort with short stop margins. Saved fuel, but at what cost? Common sense?
A more prudent approach -- in my opinion -- would have been to include takeoffs in the new configuration in the annual training cycle to ensure all pilots were proficient, and then implement the new procedure. Then, to make it better still, allow the pilot to make an informed decision and select the appropriate flap/slat configuration for take-off.
But then we might not save as much fuel.
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