So, we have started to take a look at some of the core ideals of Old-School Gaming, and how they can be applied to the modern, 4th Edition of Dungeons and Dragons. In part 3 we talked about Rulings, not Rules; I believe that the rules in 4E are solid and provide a great foundation for the game, and if you know them well, you can make consistent on-the-fly rulings for whatever action your players might want to take. Now, in part 4, we will look at the next Old-School maxim: Player Skill, not Character Abilities.
This is a big part of what defines Old-School Dungeons and Dragons. The Players' ability to ask the right questions as they explore their environment is a huge part of this. Also falling under this category would be things like solving puzzles and riddles, mapping the dungeons as it is explored, and dealing with NPCs. Probably the best and most infamous example of this would be the classic "Tomb of Horrors" dungeon. It is notorious for an abundance of "save or die" traps, and for being generally exceedingly difficult. However, what's so important about that module is that character level and ability is generally unimportant. The difficulty lies not in the strength of the dungeon's monsters (of which there are very few), but in the deviousness of its traps. It is perfectly possible for a group of very clever, low-level heroes to defeat Acererak.
Now, obviously, some Character Abilities have to be defined and have a mechanical function in the game. This should largely be limited to combat maneuvers and spells. When a player is allowed to just make a "Streetwise" check to gather information when they arrive in a town, instead of meeting various NPCs and doing the questioning themselves, something very intrinsic to the game is lost.
Now, I'm not advocating for eliminating 4E's skill system. Far from it. I'm just saying that's it's often misused. In fact, it could be used to great effect in an old-school style. Take the previous Streetwise example. Instead of just handing out information because a player made a good roll of the ole D20, instead, they learn just enough to know who they need to go talk to in order to get the information they're really looking for... and then that scene can get role-played out, for better or for worse.
Ditto for 4E's "Skill Challenge" mechanic. The Skill Challenge should be a framework for role-playing out a scene. It shouldn't replace role-playing at all! Unfortunately, that is how it is often played, and the game is poorer for it.
So, the trick is to bring player skill to the forefront and let the mechanical character skills operate in the background, as support. Force the characters to interact with their environments beyond the rolls of dice. That's old-school.