Racial Exceptions

There's been discussions on at least two different forums about race-as-class versus race separate from class. And, since "race" in D&D typically means ability score bonuses and other bonuses, it's got me thinking about how much I dislike the bonus approach to differentiating races. I won't go into that, because I've gone into it before.

But what I've been thinking about is whether a race is better defined by weird exceptions to rules, instead of mechanical differences. For example, the original elf has two features that aren't mechanical, but do affect play:

1. Elves can wear magic armor and cast spells, in contrast to human magic-users;
2. Elves can "split move and fire" on foot, instead of on horseback (in other words, they can move and fire arrows at the same time.)

With those two exceptions, even without any other racial benefits, elves seem different from humans in ways that humans can never achieve. If, for instance, you use the "+1 when using swords" rule for elves, level human fighters can match or beat that effect, just by gaining experience. But human archers can't learn to fire arrows like an elf... and, possibly, elven archers can't learn to fire from horseback the way human mounted archers do.

What I'm thinking is: what about defining all races (or even unique human cultures) this way, avoiding skill bonuses and sticking to exceptions from the norm? Halflings, as their schtick, could be "hide even in plain sight". What would the dwarf and orc exceptions be?

I think a general rule could be that any unique race gets one free exception, plus one or more additional exceptions that work as "swaps" (like the elven "split move and fire" exception, which swaps firing while moving on foot and firing while riding a horse.) The main exception doesn't have to be a swap (like the elves and magic armor rule.)