You're saying that this grants narrative authority in that the results of a successful attempt are already codified. But that's not a question of the PC having special authority - the codification of the results of certain actions is inherent in having rules written in the game book. That's no different than the authority of how the trip rules worked in 3.5, where they were combat actions that anyone could attempt at any time.
Yes, but the design of 3.5 made it so that a character designed to trip succeeded most of the time, and a character who wasn't failed most of the time. That wasn't the sort of play that 4e wanted to support. 4e made it so the optimal play was to trip once in a while. A character who wants to trip a lot can choose more than one trip power, or use the stunting rules.
Also, codification of results is inherent in the rules, but codification of narrative is not. Results is "get a +2 bonus to your next roll", narrative is "I struggle mightily and free myself from the dragon's jaws."
I don't see this as being inherent to 4E powers - I see that as being an issue with game rules versus adjudication in general. Greater codification of what mechanical actions have what results (on a success) aren't an issue of associating those with an in-character action. The trip rules were black and white in 3.5 and 3E; so why move them to being a once-per-fight mechanic in 4E?
Because you don't want people to trip each other all the time? It's about the rules supporting the end result you want to see, not about supporting the process that produces the results.
Plus, "trip is now an encounter power" is incorrect anyway. There is no "trip", there's a simply putting the prone condition on the target. And that can be accomplished by stunts, at-will powers, encounter powers, or daily powers.
Sure, and issues of managing limited resources are a fun way to put tactics into combat. It's just wonky to me when the resources being so limited are physical character actions, particularly with no explanation for how that works from an in-game standpoint.
But your actions are NEVER limited, which is the point I keep trying to make. You can do your Spinning Hurricane Slash every round if you want. But only once during the fight is it going to have the special effect described in the power. Every other time, the attempt's resolution will be controlled by the stunt rules and DM negotiation.
Quite simply, you can do whatever you want, but you only have the power to dictate the resolution method if you've expended character resources to do so.
PCs already have the ability to try anything though; that's implicit in playing an RPG. Likewise, rolls to determine success or failure aren't the issue, so much as it is an issue of why characters can only make certain attempts to perform something a limited number of times per day. It's unintuitive to say that a physical ability is limited because of metagame rules.
Once you no longer conflate "character resource" with "an ability to narrate an attempt", it's all fairly intuitive. But, as KM pointed out above, it's an aesthetic that many players don't wish to embrace.
I'm not talking about divorcing character-specific abilities from character classes/levels. I'm talking about divorcing areas of player narrative control from character-based mechanics, which are presumed to be associated. Nagol's post, above, is a good example of this - the player can write areas of the narrative, completely apart from something their character can do, with the only metagame limitation (though I'm sure there's a limit on how often a player can do this) being that it's related to their character's area of expertise - but that's a metagame limitation on a metagame power, rather than a metagame limitation on a character ability.
Yes, but they're connected by the fact that they are both metagame powers to bolster the character's story. Nagol's example can describe a planet because his character is supposed to know about planets, and being able to assert a fact about the planet directly supports that story.
A fighter with "Come and Get It" is a exceptional warrior, who attracts attention from other combatants so that the warrior can prove his superiority. The player is using the power so that the character can have a scene that showcases his character concept. (Plus the tactical implications, of course.)