Mark CMG said:
That seemed like that would allow players to know quite a bit more than they normally would about opponents, at face value.
There /is/ that trade-off, but having players roll all the dice adds new elements of fun to the table: the players get to "control" whether or not the big monster hits them or not. There is just something priceless about watching the look on a player's face as he rolls a 1 on his Defense Check . . . and then has to roll again to confirm that the monster critted on him. I find it much more fun than rolling that natch 20 behind my DM screen.
And my players LOVE it when they roll a 20 on a Defense Check and miraculously avoid getting hit by a big, devastating attack. And then there's also the hard choice to be made if the player only rolls OK, and has to decide whether or not he should spend an action point to boost the Defense roll.
As an aside, many years ago I played a few games using the reverse approach: as DM I made all the rolls, and the players didn't even have access during the session to character sheets with hard game info -- it was all just descriptive information. This was inspired by an old Dragon article by Ed Greenwood.
So, instead of Str 18, Dex 7, Con 8 the sheet read something like "Growing up, George was easily the strongest man in his entire village, but he was somewhat clumsy and got hurt fairly easily."
It was a pretty neat variant as a change of pace, and really forced the players to think like "narrativists" rather than "gamists."
The problems with this approach were it made DMing about an order of magnitude harder, and also for many, many D&D players the gamist experience is their primary source of enjoyment from the game.