But if the player becomes arbiter of what will work and what will not, then of course there will be imbalance
In which system? Perhaps in 3E/PF. Not in 4e, in my experience at least. Nor especially in Rolemaster, in my experience. And I think many people like to play other versions of D&D too in a fashion in which player contributions to arbitration of what will or won't work don't lead inevitably to imbalance in the game. Hence they try different styles from your own, and hence they encounter fighter vs caster problems. Telling them they're doing it wrong, or that they're inept, when they're trying to play in a completely mainstream RPG style, isn't really helping them.
Whoever wrote the Goad feat, or the PHBII knight, or various other things like those.
Those aren't mind control, they're mechanisms for adjudicating NPC and monster reactions.
The DM decided when to roll the dice
In any game I've played in, a player can decide when to roll the dice. Here is one example: the GM describes the room that the PC is walking into, including the fact that within it are two orcs. The player of that PC then says "OK, I cut them down, starting with the one nearest to me!" That player has decided to roll the dice - in the case of D&D, a d20 attack roll.
Their degree of protagonism, as you put it, should not be considered as a function of the rules, but of the rules and the participants at the table. If a DM wants to make a particular character a protagonist, or make all of his PCs equally so, or defer that decision in some manner, all of those are fine ways to go.
I don't see that anything is gained by restricting all players of the game to one approach
This whole thread, together with the dozens of others like it, is proof that
there is no "neutral" rule set of the sort you describe. In particular, player protagonism that is a function of the GM, rather than the rules, is not really protagonism at all - as I know from my own experience, it is vulnerable at myriad points as the GM comes under intolerable conflicts of interest due to the conflicting demands of maintaining antagonism and adjudicating fairly.
By insisting that the rules of 3E/PF not change, you
are restricting all players to one approach - namely, one in which GM force is required to balance casters and fighters. That's a fine approach as far as it goes, but for those who want to play a different sort of game 3E/PF won't deliver. As I've said, achieving protagonism via GM force, while not quite contradictory, is an extremely unstable base for satisfying play.
OK, let me present a very heavy-handed approach. The PC's are 7th level. The DM presents a challenge. It is an attack by 2 Goblins who charge the PC's from three full move actions away.. Will the dice decide the outcome, or did the GM decide the outcome by selecting an adversary that presents no real threat? Perhaps the DM decides the next challenge will be thee Ancient Red Dragons, swooping out of the sky and attacking the PC's. Will the dice decide the outcome, or did the DM decide the outcome already by setting an unwinnable threat before the PC's?
A good GM will not likely set either of these challenges, as they are not suitable to the players.
4e, at least, has rules - guidelines, if you like - for the GM. It says, "Within these parameters the game will deliver what it promises. Step outside them, and we - the designers - don't vouch for the play experience you will get". This is not an issue of GM skill, then, except the skill of reading English and then doing what it says. And conversely, a GM who reads those rules, and who still thinks that 2 1st level goblines are a
challenge to a group of 7th level PCs, hasn't shown a lack of GMing skill. S/he has shown a lack of reading comprehension.
Do the dice decide the outcome, or do the players win because they have more than adequate resources?
Rationing of resources has been a fairly important part of D&D play in most of its iterations. It's generally accepted that if the players have infinite resources (or, at least, resources that are effectively unlimited in relation to the sorts of situations that the PCs might confront) then the game has broken down, or at least deviated a long way from the norm that the designers intended. The old name for a particular version of this was Monty Haul.
When [MENTION=27570]sheadunne[/MENTION] says that dice decide the outcome, I don't think the comparison is to craps or snakes and ladders. I think "dice decide the outcome" is shorthand for "the action resolution mechanics" decide the outcome, with an understanding that the action resolution mechanics are not under the unilateral control of the GM. I'm pretty confident that sheadunne would accept that player skill, including player skill in the husbanding and deployment of resources, is one factor that contributes to outcomes.
The DM has the choice of how or even if to use the result of the existing action resolution mechanic. He can choose to use the mechanics, or not. Using the existing mechanic is no less "forceful". Both are equally "forceful" choices.
The notion of "GM force" was introduced into this discussion by me, [MENTION=6696971]Manbearcat[/MENTION], [MENTION=205]TwoSix[/MENTION] and [MENTION=16586]Campbell[/MENTION]. By "GM force" we mean what [MENTION=6696971]Manbearcat[/MENTION] has described about half-a-dozen posts upthread, namely, the imposition of the GM's will onto the fiction in disregard of the outcome of the action resolution mechanics.
Your contention that the GM can choose how or whether to use the action resolution mechanics may be true of your game - which would be Exhibit A in proving the hypothesis that your GMing approach deploys a fair amount of GM force. But that contention is not true, in general, of D&D play (Lewis Pulsipher explicitly and vehemently rejects it in his characterisations of his preferred approaches to D&D in early White Dwarf articles), and it is not true of how I approach the game. Their are action resolution mechanics. The players are entitled to deploy them. As GM I can say yes instead of having the players roll the dice. As GM I can lead the discussion around whether or not a certain outcome is feasible within constraints of genre and tropes (eg "What's the DC for jumping to the moon?" impossible at 1st level, let's talk again once you're in Epic tier). But I don't have any general authority to suspend or disregard the action resolution mechanics. And therefore have no general authority over the content of the fiction.
And what is not true in general of D&D play, is even moreso not true in general of RPGing.
None of which remotely resemble any form D&D or are in any way relevant to this discussion. I'm saying it's fundamental to the role of DM, which is D&D-specific. Correct me if I'm wrong, but there are no versions of D&D in which the DM does not have the powers being described here.
I've given two examples: Gygaxian/Pulsipherian "classic" D&D; and pre-Essentials 4e. And I think many people have played 2nd ed AD&D and 3E in this fashion too, carrying on norms learned from earlier D&D play, or importing norms from other RPG experiences. The particular style of play you are describing has never been the only or even the only mainstream way of playing D&D.