Without opening a massive can of worms or writing a thesis on the matter, I think you have to first identify what "xp" represents before you can justify what gives how much "xp".

If you gain xp for combat, and that xp adds up to levels that provide further combat prowess and additional stats such as health resource, then I disagree that thinking of doing something clever and hitting a button to eliminate a room full of bad guys is equal to or greater in reward than the combat hardening you would get from battling all of them in a face to face encounter.

In contrast, if xp has nothing to do with combat prowess and additional health resource but is instead a literal representation of a character's overall experience as "an adventurer" (for lack of a better term) than I could agree that hitting the gas button and using reasoning to avoid danger and potential harm is as rewarding.

It boils down to the fact I think the title of the thread is appropriate; "Reward Systems". To expand character progression and reward them for doing something more than lifting up a choice weapon and making someone close by bleed you need to implement more than one reward system in a given game. I have always had a problem with the general catch-all "experience" stat; if just thinking of something clever rewaded combat competency and greater stamina/health, then members of political think tanks should be able to go toe to toe with amatuer MMA fighters (yeah, that makes loads of sense there, doesn't it?)

Originally posted by NickPalmer:

A mechanic I think a lot of games need to think more about is what it rewards the players for doing.

I just feel like we need to reward players for clever thinking. Nothing bothers me more than the clever way to get by an obstacle giving you less rewards than brute forcing it.

If I hack a panel to gas a room full of enemy soldiers, I should get as much if not more xp than if I fought them.

Every time we reward a player badly for thinking clever, it reinforces the idea that he should just brute force the game.

I agree with the idea that you should get exp in your example, but I would disagree with getting more for it. It's two different ways of playing the same thing, the same amount of 'bad guys' were defeated, so the same exp should be given.
A close example I'd use in a more recent game would be defeating an enemy in Fallout 4 (just using it's experience system). If you shoot it and it dies, it's x exp, if your companions kills it you get the same exp, if you set a trap you get the same exp.
Technically a character that "brute forces" the battle learns better to utilize that tactic, where a person that hacks the vents doesn't get the experience from physical combat, but gets the experience of using a building system to do the job. Either way, the same amount of enemies died.
TL;DR version - "rewarding for clever thinking" to me just seems to be a way of trying to get the person playing your game to play it in a specific manner, whereas generalizing the experience system a bit more could end up be more rewarding to more people instead of slanting it towards a specific play style. Though, in the end, it really matters what the type of game this system is going into. e.g. if you're playing a stealthly-spy RPG, you'd want to reward stealthy actions more.