1: Elves and Halflings can be Clerics, which doesn't make sense because everyone knows they don't have souls.
On a more serious note, they are restricted to d6 HD max, which means you'll never see a Elf or Halfling Fighter. The cleric is the option that levels up faster, has spells, better saves, and a practically identical weapon list. It's funny that cleaving closer to nostalgia/eliminating these options are the fix for this problem. OTOH Dwarf clerics are fine, simply because they don't have the HD restriction (and that is the fighter's whole thing, and per above a very important thing).
I recommend either keeping the Elves and Halflings restricted from being Clerics, or giving the fighter an additional boon: The critical hit. Per the standard rules a 20 is only an auto-hit, not a critical. I would say it should be a critical hit (which simply means max damage) for a Fighter (single or multi class) and the Fighter alone. Fighters also get the auto-hit (standard rule) on a 1. I am beginning to warm up to this second option. It reinforces the Fighter's role and grants him a unique ability - just like every other class. It also requires zero math
2: Percentile rolls suck, so Thief abilities are better restated as Saving Throws with near-identical odds. Let them be able to mix in ability score bonuses, preferably a healthy mix instead of just adding Dex to every check, and probably shouldn't be set in stone. Sometimes having a high Charisma could add to Pick Pockets, sometimes having a high Intelligence, etc. Subtract their worn armor value from this number as well, and lighten up on their restrictions a bit. Sure you can wear chainmail, nobody's stopping you, but you ain't as good with your skills when wearing it.
3: Group d6 initiative, with option of simultaneous initiative on a tie. This is very close to how the game does it. Individual initiative is a chore and Dexterity boosts enough stuff without Initiative.
And that's how I'd fix Basic Fantasy. Not a whole lot of additions required.
And some will disagree with me, and that's fine. Bottom line is that Basic Fantasy should be the core game of the OSR. It's not my favorite game in the OSR, not even my favorite B/X clone, but it seems like the perfect mix of B/X and modern sensibilities. No Alignment and ascending AC. And a killer price point.
