Mechanical balance may be what you're talking about, but it's a very narrow-minded and myopic approach to gaming and game design, particularly in role-playing game design in which the overall macro-level experience is more important than micro-level mechanics.
Well, you're free to believe that. But, pushing off game mechanics design onto the DM is lazy game design AFAIC. Mechanics, lead to the macro level experience. Bad mechanics, unbalanced mechanics, result in poor overall macro-level experiences. So, no, I do not think that macro-level experience is more important. Get the details right in the first place, and everything else falls into place.
The hobby is littered with poorly designed games based on what you are advocating. Without robust, balanced mechanics in the first place, these games will continue to litter the hobby.
Wait, there are balanced campaigns, now? What?
Please try not to be deliberately obtuse when reading. By balanced, in this sense, which I actually go on to explain, it means that equal amounts of time are spent on the three pillars of the game. But, sure, feel free to play silly bugger pedantic games if you think it will help.
Unless you, you know, take into account the difficult of acquiring two good weapons, or the value of a shield. I mean, it may be good, even too good, but not to the extent you're getting at.
Yes, because it would be so difficult to find a longsword and a short sword. The value of a shield is +1 AC. That's it. That is the complete value of that shield, in 2e. So, for 1 point of AC, I double my damage output per round. I'm thinking that's a pretty good exchange. There's a reason that 3e nerfed the crap out of 2 weapon fighting.
Weapons, being very explicit in their statistics and function, can occasionally be the exceptions that do meet the criteria for "unambiguously better". However, their impact is usually pretty small. And even in this case, I think it's implicitly clear that this was a conscious decision made for a defensible reason (to encourage the use of a classic weapon, or to simulate the utility of that weapon compared to some more esoteric and less useful ones). After all, all weapon choices are not perfectly balanced in real life, nor in fiction, so why would they be in a roleplaying game?
I would point out that in earlier D&D, all weapons did the same damage. End of story. In 3e and later, weapons were all balanced against each other. A battle axe is not a poor cousin to a longsword in 3e because of the increased crit modifier. OTOH, in AD&D and 2e D&D, the longsword was flat out better than anything else you could use. Out damaging, out hitting and out magicking everything else in the book.
That's what happens when you don't pay attention to game balance.
Unless you, you know, need to make a ref save. Or get stripped of your items. Or need to get somewhere quickly. Or the DM and the player actually play out some roleplaying requirements for maintaining the cleric's faith (and your powers). Or the cleric is hunted by powerful enemies because of his faith. Personally, I do think monks pretty clearly need the boost to full BAB, but even this extreme example isn't true all the time. Clerics are generally a little bit better than monks, but that doesn't mean the rules need to be rewritten to change that.
So, all those analyses showing clerics and druids as tier 1 PC's and monks as Tier 4 or 5 are all mistaken, and you're right. Because I might have to make a Ref save? Or I might get stripped of items? ((Which doesn't actually hurt me that much - only stops me from casting spells that need a divine focus - never minding that there are numerous spells out there that let me CREATE holy symbols)).
Of course they don't. Where do you think that experience comes from?
Trying to "whitewash" the individualized, creative, open-ended nature of the game is why people don't start games in the first place. And, as with most anything in life, if you aren't willing to risk making mistakes, you won't accomplish much either.
Personally, I've had the experience. I've had (if only rarely) players that made genuinely unbalanced characters. I've made one myself. And in no case would "balancing" the rules have fixed the issue, nor did I try to avoid responsibility for the quality of my game.
Um, I'm not.
Well, considering from your own admission, you've rarely had players who made unbalanced characters, how do you actually know that you wouldn't be overwhelmed?