Right.
Well, it's not completely in the hands of the players. But I want as much there as possible.
So, as an example, my RPG uses Knowledge skills (like 3.X does). So if someone makes a Knowledge check to see if their character is aware of something (as compared to research, or the like), the checks follow very vague guidelines (different DCs representing different levels of proficiency -Competent Professional, Skill Professional, Master Professional, etc.). But that's because Knowledge is used to know about setting, and setting it determined by the GM, and varies greatly. I can't write out concrete DCs (DC 15 lets you know about bears!) because each and every GM has their own take on their own game world's setting. So I am forced to leave it vague, meaning that the GM's judgement is mandatory.
On the other hand, everything else I can take away from the GM, I do. I want objective DCs when I can get them. So, how hard is it to gather food? What about in different terrains? In different seasons? What's the temperature? Has the area been picked clean? Is food in the relevant season to be found? Is it particularly lush? Well-traveled? Are you moving quickly? All of these are modifiers to the DC to find food, and the players can look them up and take them into consideration before deciding if they want to gather food, if they would rather roll or take a 10, if they want to take a different route, if they want to move quickly or slow down, etc.
The GM still sets the setting, of course. The GM does get to determine what food can be found where, and what the terrain is, and what the season is, and the temperature, and if it's been picked clean, etc. Because the GM does run the world. But players can do things to mitigate GM interference (feats to eliminate penalties from bad terrain, seasons, etc.). They can explore the setting and use that knowledge to mitigate these conditions in the future.
The GM's judgement is still part of the game. It's a required part of it. Just like player judgement. But I want to hand over as much information as I can to my players (transparency) -usually in the form of objective DCs- and then give them access to character builds where they can leverage explicit rules to their advantage, without getting permission from the GM.
I want them to be able to say "the DC is normally 18, but my Adapted Skill feat reduces the DC to 15, and I get +6 and can always take a 10 from the Consistent Skill feat. I take a 10, get a 16, and succeed. And barring outside circumstances (fatigue, or attribute damage, or whatever), I always will succeed." And I want them to be able to do this on their own, without my input.
Well, even my skill challenge system is more structured than 4e. The number of successes necessary is set based on:
(1) Who is participating, and if they can succeed at all the skill checks by rolling a 0, 5, 10, or 15.
(2) If they're acting quickly, or under tight time constraints.
(3) If they're trying to keep their actions secret.
These modifiers determine the DC. The players have control over how quickly they're acting and if they're trying to keep their actions secret, and so explicitly have control over the difficulty of the skill challenge. They also have control over who is participating (and can leave out incompetent PCs, if they wish), and can look up DCs to see how hard the skills will be, and thus can make a very informed decision on (1), as well.
My system also explicitly calls out situations that are resolved via skill challenges (like chases or outlasting a storm), with lists of the most common skills to be used in those situations and what those skill uses will be (like Land checks to catch up to someone or Craft checks to jury rig a shelter). So, my system probably wouldn't resolve Manbearcat's scenario using a skill challenge (it'd just be skill checks).
Anyway, I hope some of that was enlightening.