Last year I wrote that skill systems aren't always a good idea. That piece primarily advocates the old-school approach to handling character interaction with the environment, in which the players' descriptions of what their characters try to do determines what they find, rather than the result of a roll. Since I wrote that I've left behind the D&D ghetto[1. "D&D ghetto" isn't supposed to be derogatory in this use, just descriptive. mxyzplk describes the D&D ghetto well and fairly: "It’s the only game they know, or the only game they’ve played, or the only game they can find a group to play. ... As a result, many different groups try to get their favorite jones – deep immersion, or gritty realism, or cinematic cool, or gamist challenge – using it." The upshot is that many people "know" that D&D does their play style just fine and can't imagine it being flawed, or that there could be any point to using any other system. I know—I speak from experience!] and have used different systems, most of which include skill systems. Many of these I've enjoyed, and I've found that the inclusion of perception- or search-type skills haven't harmed the immersion I aim for or dissuaded players from creatively interacting with the environment. I wasn't able to put my finger on the difference between "bad" uses of skill systems and "good" uses, and it's been nagging at me for a while.
Randall's post Old School Gaming and Skills at the RetroRoleplaying Blog made me realise what the difference is. The key is what I call a "fiction first"[1. The term "fiction first" is clumsy. Coming up with pithy names has never been my strength, but I haven't been able to find an established term for it. If anyone knows of a good set of terms for games that use the mechanics to represent the fiction, and games that treat the mechanics as the "physics" that determines the fiction, I'd love to read about it.] approach to gameplay: the player describes what their character is doing in ficitonal terms, and only then does the GM call for an appropriate check. The difference between old-school play with and without skills is just in how the GM follows-up the player's narration. In a system with skills, a skill roll can be used to decide where the game goes next; in a system without skills, the GM follows up with additional information, and questions that refine how the character proceeds in their intent.
What made it click for me is that defining the fictional actions first, and only then figuring out what skill(s) to use and how hard it will be, is a central and system-critical feature of how the Burning Wheel's skill system functions. I realise now that much of the "bookkeeping" feel of my last session of Burning Wheel was due to my missing this point. We didn't tend to describe the really high-level events of that session that spanned months, instead just figuring out what the next step in the plan was and sorting out the mechanics to get it done. It felt like bookkeeping sometimes because at those points we were just handling mechanics without any related narration. Although it's not an old-school system, the danger that skipping narrative opportunities presents is the same in that it relies on the narrative just as much—if in a different way—than old-school play does.