Hussar
Legend
My preference is to move away from the idea of 'powers' completely, but ingrain some of their uses in other ways.
So push backs, knocking prone, doing extra [W] damage, adding conditions can all be there, but they aren't a function of power.
Instead, give fighters a range of options and manuevers to perform (as mentioned early in the thread).
THEN a lot of these modifers/extras come in depending upon other choices. Some egs.
Weapon Chosen: hit with a certain type of weapon and this can also happen.
The actual roll: Certain effects take place on a crit. I would also like to see "raises" (like Savage Worlds) where you are rewarded for hitting with a higher number.
Magic Items could also be more interesting if they can add some of these effects.
HOW one gains access to these may be open to debate. Does everyone wielding a hammer get 'Knock Back' or just Fighters, or just Fighters that have taken Hammer Expertise, or only on a crit etc. (I don't have that answer right now, BUT I would rather see the many 'power effects' dispersed into other areas of the game).
The problem with this sort of thing, is that you're dumping a whole boatload of rules processing onto the game. It's not like in 4e where you have fairly discrete rules for your character most of the time. Now you have fifteen different rules for what you can do, and that's going to add a considerable amount of handling time to combat. 3e showed that rather well.
/snip
Obviously it depends on the situation, but for any complaint that is primarily subjective (pain, nausea, etc.) I would absolutely expect different diagnoses from different doctors (especially if they are different specialties). If you try the same case in three different courts you'll get three different rulings. Objectivity is something of an illusion, regardless of what domain you're in. That's especially true in a fantasy roleplaying game.
Again, if you're getting three completely different responses, there's something SERIOUSLY wrong here. And why would you go to different specialists for the same problem? But, in any case, if the first guy tells you you have a slipped disk, the second guy says you have appendicitis, and the third guy is talking about your spleen, you REALLY need to find a real doctor.

Really? I don't expect a typical response for even the most basic action. If I'm playing zombie horror, I expect that I can shoot and nail a zombie in the head reliably. If I'm playing CoC, I expect that I'll rarely if ever inflict harm on anything, even if I'm making an attack with the same bonus against a walking corpse. If I try to convince a guard to let me into a prison, his response depends very much on whether the game I'm playing is high adventure or hard realism. It all depends on style, on what kind of story you're telling.
Now you're moving the goalposts though. As you said, I would expect different results from entirely different genres and games. I would not expect D&D to work the same as Vampire or GURPS. That's a given.
However, if two groups are playing D&D, and they are doing fairly common D&D actions, such as trying to hit something with a lumpy metal thing, then I would expect the responses to be pretty darn close.
Even your example of talking to the guard, should get fairly reasonably close responses from the DM - you make your bluff/diplomacy check and go from there. I wouldn't expect, however, to suddenly have to roll a D100 and compare to my combined CHA and Diplomacy scores.
How is this different? If the goal is to win, the wizard should be saying "I cast a spell", "I cast a spell", etc
A wizard spamming magic missiles at a monster with 50 hps, is not different (except in flavor and the fact that the wizard eventually can't anymore) from the fighter saying "I attack with my great sword"
The trick though is that the wizard will NEVER spam magic missiles. He's got a bajillion different tricks in his bag, most of which are significantly BETTER than magic missile. As he goes up levels, his tricks all get more powerful. The fighter's tricks actually get LESS powerful as he goes up levels - tripping is great at 1st level, far less useful at 10th level and virtually impossible to pull off at 20th because the monster's are virtually untrippable due to size and other bonuses.
Unless, of course, the fighter laser beam focuses on trip to the exclusion of virtually anything else.