Certainly can't tell fellow gamemasters how to do their job. But ... I always suggest to new GM's, or GM's looking to improve, "Never let the rules get in the way of a good story." An even better caveat is to drop the word 'rules' altogether. 'Mechanics' is much more elegant. Mechanics are guidelines to assist in addressing any of the myriad scenarios a GM wishes to tailor. And the Adventure System effectively provides a universal set of those guidelines. The authors go out of their way to directly address almost ANY action/scenario/event/challenge in ANY campaign/world/play setting that you can think of. In the event that a GM or his/her players do come up with something that isn't specifically accounted for, once again, the fundamental mechanics for resolution remain unchanged, and can be applied.
Can only speak for myself, but I got into adventure role playing, to adventure role play and either tell, or experience a story ... not to be an accountant, or min/max, debate or argue every attribute or obscure circumstantial modifier to assist in determining outcomes. However, for the number crunchers amongst our community, Adventure System allows for either a very basic application of determining difficulty, or one can go as far down the situational rabbit hole as one chooses. For all intents and purposes, the fundamental mechanic for Adventure System is allows the GM to assign as provided in detail, or determine difficulty numbers which the players attempt to match or overcome as determined by their stats and/or skills. The fact that players can see improvement with virtually every session tends to keep their interest and engagement high. I appreciate that the authors here, actually specify assigning experience based on good play, interaction via role playing, etc. rather than experience being determined by how 'hot' a players dice are.
I recognize that the same can be said for virtually all gaming systems, target number, plus mods, or minus penalties, but Adventure System streamlines this so that there is more mayhem, and less math. With my play group, within 2 sessions, they settled into character and story, rather than being concerned with the statistics side of their character sheets.