Here we see that, while mechanics are important, engagment with the fiction is permeating the whole episode, and shaping the way that mechanical resources are deployed and that deployment adjudicated. In particular, it was in virtue of the fictional situation that the wizard player needed to find a mechanical means of using Nature at range, and that the sorcerer player needed to find a mechanical means of using Intimidate while backing away.
Odd. I see a purely gamist construct from start to finish with the mechanics defining the fiction. You choose the version of the bear based on what would make for a good game encounter, not what made sense in the context of the world or what would generate an interesting story or plot beat. Then when the players decided to deal with the bear without attacking it, you converted it from one mini-game (combat) to another (the skill challenge), while retaining the same (more or less) level of risk-reward. Then when the players declared their actions, you and they bargained back and forth to find some fictional cover for allowing their mechanical actions to have the desired effect regardless of the realism or the dramatic concerns of the game or the story conventions it's trying the emulate. The fiction is being manipulated to fit the mechanics used.
The water weird
The PCs were investigating a hot spring inside a temple bathhouse, and were attacked by a water weird. I had already decided, in my prep notes, to resolve this as a complexity 2 skill challenge ie 6 successes before 3 failures.
Wait, why does the temple bathhouse have a monster in the hotspring and why is it attacking the PCs? Has the temple been abandoned and it's moved in by chance? Or is it some sort of guardian there to protect the holy spring? Or is it there because you want to run a encounter and give a chunk of XP out? What's the goal of the scene for the player characters?
The PCs quicly discovered that psychic/Will attacks had no effect - the weird was animated water, with no discernible mind or body. So they decided to (i) try and destroy/move the water, using radiant and thunder attacks, and (ii) to try and plug the spring, by knocking stones down into it and using the thunder attacks to drive them home. (In my prep notes I'd expected the PCs to try and expunge the spirit, and had made some notes on how Religion and Arcana checks might play out. The idea of plugging the spring instead came as a surprise to me.)
None of this makes sense beyond a game construct. It's immunities seem somewhat arbitrary, and allowing holy power (if I understand radiant right) and noise (unless thunder means electricity, which also doesn't make much sense) to effect the water seems equally arbitrary. Although your comment about expunging it with a Religion check implies it was some sort of demonic possession, so maybe radiant makes sense. That plugging the spring would work is hard to value, since you haven't explained why plugging the spring would have an effect.
A question to other GMs - especially those who don't like structured non-combat resolution (whether 4e skill challenges, HeroWars/Quest extended contests, etc): How would you adjudicate an attempt by your party to defeat a water weird by plugging the spring at the bottom of the pool containing it?
Well, I'm not clear from your description why plugging the spring would stop the water weird. It's also depends on the point of the scene. For simplicity's sake, I'll assume the NPC is just there in the bathhouse of an abandoned temple as a risk of exploration. Similarly, I'll assume the players have gotten a Hint (capitalized for a reason, it's a mechanic in my game of choice) from me about how to overcome the NPC and haven't just entered 'F-it mode' and bought a Flash-Forward.
From there, it depends on the player's actions. If the player asks if there are suitable rocks to block the spring, without spending Action Dice to declare said rocks exist, I'd decide if there are any lying around via a simple die roll, a roll on the Fate Chart (from the Mythic Game Master Emulator), or my whim. I'm currently a fan of the Fate Chart for this though.
If there are rocks, I'd make a quick assessment of how the fight's going and how many rounds I want it to take based in the needs of the scene and how much of a pounding the PCs are taking. A quick check about it's weight might come up to see if it's lift-able or has to be pushed, or I might decide it based on dramatic priorities for the scene and what feels more interesting. The map and description of the scenery would probably strongly inform my choice of location. From there, I know the PCs ability to shift rocks and they can make Athletics checks to increase their effective strength for doing so. If they're just looking to knock it over (again, it's hard to say without looking at the map or being in the moment) I'd either just have them push it 5 ft or so, or figure out how hard a challenge it is and grab the Sliding DC for that difficulty and call for an Athletics check from whoever wanted to try. This would most likely fall to a strong PC, since the spellcasters really only have Gust of Wind to shift it and casting Brawn on the strong man would probably be more effective.
If there aren't rocks and the PC wants to make some, I have rules for damaging scenery, then see above.
As for reward, well assuming the NPC is just there and they didn't achieve any goals beyond defeating the elemental, they get the Elemental's XP (which they would have gotten by any means they rendered it hors de combat or even by talking to it and coming to some accord other then surrendering or fleeing). Treasure depends on too many factors, but just playing vanilla they don't get any either way since Elementals don't have treasure.
