That's the ideas generated off the top of my head (in the last hour or so). I'd welcome anyone who'd like to share any more. I'll add them to the list after this point, along with any other factors that occur to me as the days go by.
- Thou Shall Find Thyself a few Good Men (and Women): The henchman rules in 3rd are far too restrictive for old school play. 7th level and a feat just to get yourself a henchman? No, a character can have as many henchmen in his career as his charisma modifier plus 3. The Leadership feat, as written, is what happens when your character builds his stronghold and achieves level 9. The leveled follower from the Leadership feat does not count towards the maximum henchman total. And as for hirelings? well, the pay rates are there. Knock yourself out.
- Thou Shalt Roll But 3D6 and in Stat Order: In 3.5 and Pathfinder, players get to roll 4D6 for each stat, dump the lowest and assign the scores wherever they like. The result is a swathe of above average characters who excel in their chosen field: every wizard stronger than he is smart and every cleric as wise as Marcus Aurelias. Not in my game you don't. I like wizards who could have been more successful as a circus strongman and fighters who perpetually suffer from the common cold. It's called having character.