- Elves: +1 to hit vs. common humanoid foes. fighter/MU versatility
- Halflings: +2 AC most of the time, +4 AC vs large foes, +2 to hit with missiles, substantial save bonuses
- Dwarves: +2 AC most of the time, +4 AC vs large foes, +1 vs common humanoids, substantial save bonuses
This is somewhat balanced by level limits. However, lets face it -- many campaigns will never reach level 7 (out of 10), where the Dwarf level limit becomes an issue, for example. The demihuman bonuses are also all stacked up at first level. For example, a human fighter would have to get to level 5 before they are better than a first level halfling at missile attacks! A dwarf or halfling in plate and with shield is effectively AC 21 against giants and AC 19 against man-sized foes, making them almost unhittable.
At a quick pick-up whitebox game, we decided to give human characters +1d6 HP at first level. I think this is a decent idea: it is different from a straight AC/to-hit/save bonus (which is what the demis get) and makes humans pretty desirable as first level survivability is iffy at best anyways. It also is a benefit that fades out over time -- it is very significant for levels 1-4 then becomes less so, which is perfect because level limits kick in to balance demis at the mid to high levels anyways.
The issue with this is you can get REALLY lucky rolls. For example, I was playing a MU and got a roll of 5 and 6 for HP: 11 HP at level 1 as a MU significantly changes the feel of the class. I was somewhat fearlessly wading into melee with my quarterstaff in hand, safe in knowing that I could take a few hits.
I think going forward what I'll do is give human characters a +3 HP kicker rather than +1d6. This accomplishes the same goal of boosting humans a bit at level 1 but prevents anyone but a fighter from getting double-digit HP right off the bat. The random solution I suppose would be to give them a +1d6 HP "olympic scoring style" kicker but to roll three dice, discarding the lowest and highest and taking the middle.