And then I want RC to see your point, that encounters that make the PCs feel like there was nothing they could do are bad.
I do see what you are saying, I just refuse to accept that, unless there is a die roll involved, the players can do nothing.
It is definitely true that, if the DM wants to kill you, he will kill you. That is bad DMing. Not having SoD effects in the game will not help you.
If we discuss SoD from any standpoint where it is assumed that the DM isn't out to kill you, it follows that the DM
wants the players to anticipate the SoD effect. In this case, the players always have a plethora of options available to them. These options don't necessarily involve rolling dice.
As an obvious example, the room with the 50-ton block (resetting, ala 3e, as odd as that may be) can have definite signs of past victims, pulverized by the block. The DM doesn't require a roll for the PCs to spot this; he tells them. Perhaps they chase a creature that stumbles into the block. Perhaps the block is ultimately a weapon that they can lure another creature into stepping under. The might not have to fight the ubermonster if they can get it under the block. The mere existence of the block creates possibilities that don'e exist without it. It becomes the gun on the wall in Act I that is fired before the end of Act V.
The film,
Clash of the Titans has another example. The medusa is a SoD monster (effectively) which Perseus has a chance of beating; the titan isn't SoD, but is so tough that Perseus needs the medusa's SoD effect on his side to have a chance. And, in the film, "DM Zeus" makes sure Perseus has the means to defeat medusa...a magical mirrored shield he can look in, a magic sword, and pegasus. Of course, pegasus is stolen by Caliban (who Perseus made an enemy of earlier in the story), because we don't want to make things too easy......
You can remove these effects, and still have a game. But when you remove them, you make that game focus more on actual combat and less on the player using his wits to avoid combats that include such dire chances. That is a real loss, IMHO. And it is a loss based upon the idea that the player believes that there is nothing he could do, which, assuming the DM isn't either out to kill you or incompetent, is false.
(And, yes, 3e had some problems, largely because the designers removed/altered parts their survey showed to be "unfun" without -- AFAICT -- really understanding why those parts were as they were in the first place. IMHO, 4e suffers from the same.)
RC