The game you're playing has rules for a reason, written by people a lot smarter than you. You should think long and hard before changing them on a whim, and should understand the consequences of changing any core rules; any rule change should have a valid reason other than "I don't think X should work that way" or "I don't like how Y is described".
And it would, if that was all that he said. However, the quote that you pulled out ignores the extra context. Someone who's designed a given game has likely spent a fair bit of time and effort doing so and quite likely has some fairly decent reasons for doing whatever it was that they did.
I've played far too many games to simply buy that anymore.
Game design is hard work, but there is no guarantee whatsoever that the people who wrote Game X are "smarter than you" (let alone "a lot").
The other part is true, though -- any game that uses "knife edge" balance (as opposed to "broad-based" balance, and including all WotC-D&D games) requires a bit of thought before tinkering with the core concepts. Indeed, I would go so far as to say "More thought than some of those
smarter than you game designers put in some of the time."
For instance, I would argue that many of the problems with 3e (that I have, anyway) came from ill-considered changes to the TSR-D&D model. Likewise, the problems I have with 4e come from (what to my mind are) ill-considered changes to the previous WotC-D&D models.
That the 4e model wouldn't solve the 15-minute adventuring day problem, for example, was discussed on EnWorld by myself and others based on the designer blogs. It was obvious (to me) that the designers had mis-identified the source of the problem. There were others (Mutrum_Ridiculy in particular) who demonstrated that the 4e design strategies could work, depending upon how they were implemented.
So, do I accept that game designers are talented? Sure. Some of them are very talented. Do I accept that they are smarter than me, or that they know better what I want in a game? Not remotely. And that isn't ego, either, because I don't accept that they are necessarily smarter than anyone else, either.
But that does lead to an important maxim:
If you want to tinker with the rules, broad-based balance games are more likely to suit your purpose than knife-edge balance ones. But, as people like LostSoul and the Jester demonstrate amply, you can tinker with knife-edged games, too, giving them a much wider base to balance on.
RC