Let's talk level limits. A common enough gripe of old school play style, generally with regard to demihumans...which is going to be the subject of this post.
[and, frankly, if you're going to gripe about assassins only going to level 15 or druids to level 14, I can't help you. Though, I suppose Gygax increased druids to 23 with the UA...because we need druids turning into fire elementals and stuff? Some stuff I just don't get...]
Holmes (my new "foundation" for all games D&D) has no level limits, of course. This is because the text of Holmes Basic only provides rules for characters up to 3rd level...and even the stingiest edition of Dungeons & Dragons (the Little Brown Books) allows the lowly hobbit to achieve 4th level. However, as I plan my Ten Year Campaign, I know that (as with multi-classing and which classes deminhumans can become) I'm going to need to make some hard decisions as to maximum levels.
I might be in the minority with regard to level limits, but I like them. And it has nothing to do with game balance, or throwing human characters a bone, or modeling human ambition as their "advantage" over demihumans. No...to me, level limits make sense based on the limitations inherent in the demihumans.
Take the halfling (hobbit) as an example. Originally, their maximum potential of fighter was 4th level. That's "hero level," four times greater than a 1st level fighter, but pretty small potatoes compared to the ranks of high level humans. But look at their limitations: limitations of upbringing, of temperament, of training (in hobbit communities). Limitations with regard to armor that can be worn and weapons that can be wielded. If I have a small frame, poor reach, bad leverage (in hand-to-hand) and an inability to wield (and thus practice) most of the large weapons available, how am I ever going to reach the potential in training for battle as a human?
Look at elves. If we consider them these stereotypical, daisy-eating vegetarians with a deep respect for life...and thus lacking a killer instinct...coupled with a love of frivolous star-gazing, woodland frolicking, and wine-drinking (the Tolkien model), PLUS a slight frame, shorter reach, less leverage, and the capacity to bruise like a peach...well, you can understand how they might be limited as well.
And the same holds true for dwarves, okay? Don't tell me these are the roughest, toughest warriors in the realm, whose "favored class" is fighter. Fighting in tunnels, hatred of goblins, doesn't provide you with comprehensive fighting skills. You can't even ride a damn horse (not that you have stables underground anyway). Your fighting education is lacking, my beardy little friends. You can still be PROUD warriors, but that doesn't make you SKILLED warriors.
Here's my take: adventuring classes are human scale. Yes, I've decided that (at least for a couple demihumans) race will not equal class, and whether due to their interaction with humans, or adventurous nature, multiple classes will be open to non-humans. However, being "human scale," only humans are able to express the full potential of the class. Even if we're talking about a world setting analogous to Tolkien's Middle Earth (where you have a history of elves like Fingolfin and Glorfindel taking down balrogs single-handedly), this isn't about elves being "diminished in the current age." It's about humans expressing the full potential of the adventuring class (though the class may have been pioneered by this "elder race"). Those heroes of an ancient age may have been hot stuff, but humans in the current setting can be even better.
Yet even for humans, there's a limit to what can be learned...a finite amount of skill that can be acquired. For my Holmes setting, the hard limit is about 14 for the four main classes (fighter, magic-user, cleric, thief), with lesser levels for subclasses. For all classes (and subclasses), hit dice stop accumulating at level 9, and only bonus HPs are gained thereafter; skills and spell acquisition cease at 14, and while saves continue to improve, combat skills stop at level 13 for fighters. This is the limits of the class, mind you...you've learned all you can learn by the time you hit a certain level, and the only thing there is to gain is a little bump to HPs and (possibly) to saves. There's just a limit to what is possible for the adventurer.
But while characters can measure their power by their level, they measure their success...and what they've learned/earned...by experience points. And here, I've decided to simply install a hard cap on how much XP can be accumulated: one million points. Once you've hit that number, you can retire or continue on, but you aren't earning anything, no matter how many monsters you kill and no matter how much treasure you accumulate. One million is, for my purposes, the limit of what adventuring can gain you.
Well, actually 1,100,000 for individuals with a 10% bonus for their prime requisite. But a million for everyone else...including demihumans, to whom I don't really want to give a prime requisite bonus (let that be the "human advantage").
Elves, as I wrote earlier, simply add the XP required for fighters and magic-users together to determine how much XP they need to accumulate to advance. With a million XP cap, that gives them a maximum potential of 10th level (at 810,000xp). Even earning a million doesn't get them to the next level.
Dwarves and halflings only have the options of the fighter and thief classes (and remember, there's no "multi-classing" round these parts). For dwarves, their normal maximum training is one-half the human potential (call it 7th level), but even after reaching it, they can continue to earn XP (up to a million)...however, each level requires double the normal XP to acquire (giving them an absolute maximum of 11th). For halfling fighters, their base potential is only one-third that of humans (4th level), and continued progression requires triple the normal XP (absolute max of 9th level). For thieves, this would be reversed (dwarves at one-third/triple and halflings at one-half/double).
This method allows the demihumans to keep earning XP along with their human counterparts, just at a much slower rate of return and (one might presume) with a higher rate of "burnout" or urge to retire...there are some awful long stretches of "no gain" as the non-humans work and work and work to try to match their taller comrades. But...well, it's a bit like the real world: I would have never been an NFL linebacker, no matter how hard I tried, because I'm just not big enough. Nor would I have ever been a genius physicist...I wasn't gifted with that type of intellect. Demihumans have inherent limitations based on their individual species and culture. At least in my game world.
But there's still bragging rights for getting a million points.