But one of the side issues that has come up is the idea of making D&D more amenable to the "lone hero" playstyle. Although it's possible to play D&D as a solitary PC exploring a dungeon (Mike Mornard brags about the time he played a solitary 1st level magic-user in Gary's dungeon,) this kind of play isn't quite like the lone hero we sometimes see in swords & sorcery or sword & planet stories. Solitary heroes usually get struck down quickly.
I think there are a couple changes you could make to D&D's combat and hit point system to make this kind of play easier.
- Multiple simultaneous opponents as in OD&D, but: Drop the 1 HD or less restriction; only require one attack roll and one damage roll; deal the same damage to all opponents..
- Multiple attackers with the same HD make only a single attack roll against a PC at +1 to hit for two attackers, +1 for each doubling of the numbers. Only roll damage once.
- Hit points are now fatigue, not damage resistance. Hits taken are erased after every rest. Hits taken greater than or equal to hit points means the defender drops, unconscious.
- Any damage roll of 5+ means physical injury to one body part (penalty when using injured limb.) Bump this up to crippling injury (can't use limb, possible death when aiming at vital organs) unless defender is wearing metal armor on location. Edged weapons actually sever limbs instead of crippling them.
- Physical injuries require time to heal. Roll a d6 after a week of recuperation and add your Con modifier; 5+ means all simple physical injuries are healed (7+ means no scar.) Crippling injuries are reduced to simple injuries. On a result of 1, one injury becomes permanent and stops healing.
The last three changes make multiple combat encounters easier to survive, but still carry some risk, even instant death or lost limbs. I'd probably let players choose where they receive an injury, or which injury becomes permanent on a bad recovery roll. I'd probably even let players choose whether to drop unconscious or fight on, with any successful attack against them after that point being an automatic injury.
The first two rules changes means that a solitary hero can fight multiple opponents without a lot of risk. With one attack roll and one damage roll affecting all opponents simultaneously, it's easier to fight your way through hordes of enemies. Taking only 1d6 damage total, regardless of the number of opponents, means that increasing the number of opponents doesn't mean almost certain death.