Yeah I'm a bad, railroading, overly mechanically oriented DM who just doesn't get anything. Thanks mate.
Just like you implied that I force my will on my players regardless of what they want. Thanks mate. The point is, all DMs force their will at points on their players and unless the DM does something really heavy handed, cutting a skill challenge short when it's obvious that with proper tactics, there is no reason for more skill rolls is no more heavy handed than continuing on with the skill challenge.
Yes, having additional skill checks will allow for additional dialog, but it's often mostly meaningless dialog. There's no deep discussion here at this point. There are no NPCs to have deep discussion with. The players had already solved the problem.
Yes, the players can tell jokes and have fun and maybe even solve some minor little additional obstacles that the DM continues to throw at them. But after the first two PCs got up to the top of the cliff, were the minor additional little obstacles really worth it to continue the skill portion of it?
Isn't it possible that some of the players felt at that point that it was basically over? That they had solved it? Was it necessary to have the last few climb rolls and "Opps, the dwarf fell and took 2D10 damage"?
As a player, I would say "Wait a second". There are 3 of us at the top of the cliff. We can lift without being encumbered 350+ pounds and lift with being encumbered 700+ pounds, but the 300 pound dwarf who has ropes tied to him and is assisting in his own climb is a problem?" To me, that's +15 to the climb skill per PC assisting and an auto-success mate.
And isn't it possible that getting to the next more important portion of the adventure would have been just as much fun or more fun for the players? Are you positive that "Nope, the players had more fun doing it my way" is actually true?
Cause I know that as a player, there sometimes becomes a point in the game where the "set up" to the real adventure is taking too long and I do just want to cut to the chase. This often happens for me when pedestrian things are happening like minor side discussions with unimportant NPCs is occurring, or when players are hashing out multiple ways to accomplish the same thing for a long time, or quite frankly, when the DM explains a skill challenge that seems like it's blown out of proportion or when the DM squeezes out the last few skill rolls for a skill challenge.
The WotC skill challenge of making Nature rolls to walk less than 100 feet north through a woods was a prime example. The first level module actually stated word for word "Any time a character makes a skill check as part of a skill challenge, another character must simultaneously attempt a DC 15 Nature check. If the Nature check fails, the party loses its way and gains 1 failure." I stopped the DM mid-explanation and asked if it was really necessary to have a SC to walk through less than 100 feet of woods. Were we really going to get lost doing that? She more or less realized that just because the SC was in the adventure module didn't mean that it added to the gaming experience.
Walking 100 miles through a wood? Sure, the PCs can get lost. 100 feet???
It was unfortunate that such a BAD SC was in this module because this was a first time DM who didn't have the experience to realize a bad one from a good one. Not that all experienced DMs would have caught it either. I suspect a lot of experienced DMs played that SC exactly how it was written in the module. And a lot of DC 15 Nature skill rolls are bound to be missed at 1st level if the players have to roll Nature each time they roll a different skill, especially if nobody in the party trained the Nature skill. That's a terrible mechanic even if it was 100 miles through the woods.
My opinion is that if WotC modules can have such blatantly bad SCs in them, that many ad hoc and designed SCs from DMs probably have elements in them which players scratch their heads over as well. Your example of forcing the last two PCs to roll the Climb checks when there is enough physical strength above them to just pull the PCs up (plus the PC is climbing as well) is just such an example. IMO.
Another aspect of skill challenges is the "high level" pedestrian challenge. Is it really necessary to have any skill rolls for 10th level PCs to climb that same cliff? These PCs are local heroes. They have climbed half a dozen cliffs by the time they got to 10th level. As DM, a cliff is no longer a challenge. I don't even bother with rolls and I don't bother with an explanation by the players of how they are going to do it. The PCs just say that they are doing it and it's done.
But I suspect that because the skill challenge mechanism is in the game system, many DMs go out of their way to create the 10th level equivalent of the cliff climb challenge.
DM: "The rock on this cliff is really crumbly. It adds +5 DC to the normal climb roll."
I would never do that to my players. At 10th level, they have better things to do than a SC to get over a cliff. A cliff challenge is for low heroic tier.