Maybe I took Wizards of the Coast more at their word than many back in the halcyon days of early third edition, when they said that the design goals for D&D were "tools, not rules."
It's always been my style to turn rules into tools anyway. I'm a bit of a free-wheeling type of GM; I like a robust system, but I refuse to allow myself to get bogged down my minutiae. In addition, I recognize two types of robustness; robust character definition and robust action resolution.
I actually prefer the former to the latter. I like having clearly defined rules defining my characters, including things like feats, skill points, etc. that help me get a handle on what my character is like and what he's good at, poor at, and generally capable of.
I don't mind a robust action resolution system, but d20 goes too far with detail, IMO. I tend to ignore a lot of the detail about how to, say, figure a DC for an activity and just wing a DC that seems appropriate for the challenge at hand. I don't worry too much about what the skill descriptions say so much as what makes sense. I worry about keeping people inside the box on actions, and rather wish my players would describe what they want to do (preferably something much cooler than "I move up and attack with my sword!") and I like to adjudicate what kinds of checks would be necessary to accomplish that.
Maybe that's a hallmark of "old skool" gaming, where DM adjudication was an expected part of the game, but that's still my expectation. I like a game that gives me robust tools to accomplish that, not necessary rules that imply that I have to do things a certain way. d20 works that way, but honestly, the books seem to imply (contrary to the statement circulated around back in the day) that they are in fact full of rules not tools and the books that say otherwise are few and far between. This has fostered a culture amongst players that these are rules not tools when I think the opposite is a very desirable situation.
What sparked this line of thought in me was my review of the Hot Pursuit! rules by Corey Reid. These most definately are tools---a modular add-on that enables classic chase scenes to be modeled pretty well in d20 (in my opinion, a rather egregious gaping hole in the current ruleset.) Corey is an online friend of mine from way back, and I actually looked at an early review copy of the rules and gave some minor feedback before they were officially published, so I feel at least some sense of (misplaced, no doubt) ownership over the way they work, and I've been anxious to implement them for some time, but haven't been running in quite a while either.
In my review of the rules, I noticed that they---like d20 in general---is a bit more robust than I need them to be. The basic concept of how chases work is brilliant. I really like it. The list of specific actions I don't need, and in fact I think actively detracts from the fast-and-loose way that I prefer running the game. Rather than utilize them (other than as examples to get my imagination working) I'm going to integrate the basic concept of the chase scene and it's basic mechanic, and then just... again... adjudicate the actions the PCs describe to me using existing skill checks and other tools in the d20 system.
In any case, if you like action-oriented games at all, I highly recommend you pick up the Hot Pursuit! pdf from whatever rpg-related pdf vendor you prefer; I know rpgnow.com has it, as well as the correllary Hot Pursuit: On Foot. Not only does it support a writer who I like and think is quite talented, but it's a nice little modular subsystem that really does plug a gaping hole in the rules and allows for chase scenes; one of the most iconic of action set-pieces in the fiction that d20 is supposedly designed to emulate.