AbdulAlhazred
Legend
It's interesting that you are only looking at it from a mechanical perspective. I think there are solutions from the colour side as well.
1. You don't do anything? Something bad happens. It might not be a mechanical failure, but it will suck.
You're running away from the dragon and you don't do anything. Fine, it eats you. You're supposed to be talking to the Duke and you don't say anything? He gets creeped out and thinks you have a secret to hide, so he starts talking to you. You still don't say anything? That's very rude; the Duke might throw you in jail while he finishes his talks with the rest of the PCs.
2. If you don't think of it in terms of "Intimidate" but instead "I put my sword to his throat and say, 'If you don't tell us who you're working for I'll gut you like a fish - and then my cleric buddy will heal you so we can find a new place to cut you.'" There is going to be a consequence to that action - indeed, there should be a consequence to any action. Play off the fictional reality of the action instead of "I roll Intimidate. Does 23 succeed?"
3. I don't think every PC should shine in every skill challenge.
4. Interesting.
Yeah, and let me reinforce that. A totally mechanical skill challenge, one where the action simply consists of a fairly static situation where the PCs are just make skill checks again and again to pile up X number of successes WILL be mechanical and probably uninteresting. At best it will be a spam fest. You can toss in a bunch of mechanical rules to defeat that, but it doesn't fix the basic problem, which is the SC very limited.
Now, there is a place for these kinds of challenges, maybe in combat or as simple 'speed bump' challenges that one or two characters quickly solve. Maybe a few other cases where the situation can be handled that way and be logical (say a race or a soccer game could work that way, though it might be more interesting done another way).
The challenge should present different 'tactical' situations. It should be built around the in-game action, not around the mechanics. Just make sure each evolving situation in the challenge requires a bit different tactics to beat.