1) It also needs to have things work as do in our world, to the extent that is relevant. For instance, gravity, yes. Magic may or may not be able to manipulate gravity, but presumably its default effects are the same. Similarly, the effects of sharp objects on human flesh should be about the same.
On the first count, sure, yes, the rules of the fantasy world need to be consistent, on the second count, no, I have to disagree. If the effect of sharp things on human flesh were about the same in D&D as in the real world, then our characters would die
a lot, and there'd be no such thing as getting more HPs when you progress up through your levels. In fact, the manner in which the human(oid) body takes damage has to be
radically different in D&D for the game to work at all, much as it has to be in almost all forms of action movies.
Having characters be able to do more than human things is reasonable, having characters be able to make things that would be obstacles to humans totally irrelevant is not so reasonable. Even Hercules had to eat, drink, sleep, and use the little godling's room.
Okay, so basically now we're haggling on what level of power is "too" powerful. Fair enough. I think that there should simply be a scale, from nearly human to (potentially) demi-god, and everything in between.
3) If being a monk requires "something rare and special", that should be reflected in the rules. 2nd edition's "minimum ability scores to take this class" being reintroduced...if properly done...might be a good idea. However, if that's the case, one should ensure that characters will generally have decent ability scores, at the least, which dice are iffy about.
I was thinking of that, too. I think the design concept in 3.x was that instead of having actual minimum scores, the classes would simply be built such that unless you had high scores, playing a monk (or paladin, or bard) would be a sucky experience. So if you have decent/okay abilities, just take a fighter. If you got lucky with your rolls and have good/high abilities, then try out a Range/Paladin/Monk. I'm not saying they
achieved that goal, but that seems to have been the thinking. The thing to do, then, is to be explicit about it. "Unless you have decent Dex and Wisdom, your monk will suck. Unless you have decent Str, Con, and Wis, your paladin will suck." etc.
5) I do have a problem with that. A foot long blade is simply not long enough to reach a dragon's heart no matter how badass you are.
Fine, then you hit a major artery, or you cut off its oxygen, or however the hell you want to explain it. Unless you want to bring in an anatomically-specific set of combat rules (please gods no!), then you're stuck with "your weapon can do X damage, and that monster has Y damage." Measuring the weapon's length compared to how far into its body its heart is would require a whole different combat system and effectively a whole different game. D&D just doesn't do that. Never has.
6) At least. As written, it starts in the 10-15 range, and is definate by the 16-20. 21+ just gets "Okay. Not even Cuchulain is that good.", which is not a good thing. We all want to play at least somewhat larger than life, but when we have characters who make the best characters of myth and legend look weak, something is off.
As long as there's a full range of power levels, then what do you care if other people play god-like?
8) Works. However, that should mean that wizard PCs are uncommon, too. Having all the PCs be mutant freaks is a tad too strange. But that should be between the DM and the players, not a "Do this according to the rules or we will hunt you down and kill you."
Adventurers
are social freaks. They exist outside of all the normal social structures, including class, economy, and even family. They are special. They are, effectively, the superheroes of a fantasy world. That's their nature. The overwhelming majority of NPCs in any given D&D world will
never earn more than a handful of hit points or learn to swing a sword with the kind of skill and power that even a mid-level PC will. That's the only way that D&D worlds make sense. When the PCs are already among that rarefied group, there is no need whatsoever to limit their access to wizard/sorcerer/druid/cleric classes.
9) The problem is that it means that eventually, if you keep playing long enough, you will reach the next tier. That bothers me. I'd like to have the threshold between tiers set up so that you have to go to some effort to cross it. Of course, if you're playing in a game of capital-L legends, you'd have the capacity to do so. It's just that "I gain xp" alone won't get you there. Being a legend is about more than just how experienced you are, after all. It's about doing legendary stuff.
The tiers, as I understand them, are relative to one another. Thus the goal is for everyone to progress at more or less the same rate. The nature of an RPG with levels is that the PCs get progressively more powerful. If you don't like it, then stop awarding XP at 6th level. Problem solved.
10) I'm not entirely sure on the boosting. As to pushing them down....one thing to do is dramaticaly limit what can be done via magic. Magic should not be a "I cast the spell of solve this problem". Tier 3 mages (used to mean spellcasters) should have spells that are capable of allowing them to solve something, but not simple "I solve this with my spell".
So the spells should be able to
solve problems, but not solve
problems...? (I have no idea what you're trying to say)
Similarly, the number of spells available (as in, the number in the game and the number any given character can learn) needs to be cut down.
That might be the way to go. Unless you want to rewrite
all the spells, this is a simple, quick way to cut down on the wizard's power. Makes it a lot less fun to play the wizard, though, so maybe the game should award more low-level spells and fewer mid/high-level spells?
The other thing that occurred to me with regard to spell-casters in general is that if you make it easier to disrupt casting, then you put a serious, in-game limit on them. In 2nd Ed., taking a hit
at all ruined casting, and because of the way rounds worked, that could happen in
any round in which a caster started a spell, not just with held actions or
1-round casting [thank you, Sunic]. Spell disruption was a major part of the risk of casting spells anywhere near combat, and it's been all but removed in 3.x. I think it should come back.
One other thing is to have magic be draining. As in, physically exhausting. Not per spell, necessarily, but a spellcaster using either many spells or one massively potent spell should feel pretty worn down afterwards.
That's not how spell-casting traditionally works in D&D. You're talking about designing a whole new game, now. Honestly, I don't mean to sound dismissive, but maybe you should work up a fantasy version of
Shadowrun? It has much more "realistic" damage rules (relatively speaking), and the "drain" system for spell-casting has a lot going for it. I have to say, though, in all honesty, what you're advocating for in this thread is a total rewrite of D&D into effectively a different game. If I wanted that, I'd just take up a different game. There are plenty of them on the market. I'm sticking with D&D because I mostly like it the way it is. There's no point in doing a rewrite so massive that it's a different game entirely, at least not for me.