As I said, this is probably going to be the most controversial example, so I understand if this isn't exactly an example you agree with. But it is relatively convenient to articulate the difference.
A different example would be Prestige Classes vs. Paragon Paths. In both 3e and 4e, these were higher-level features that you had to qualify for, and which unlocked new abilities and (potentially) synergies with your existing ones. The Prestige Class structure sought meta-aesthetics by having precise, and often narrative, requirements for entry...and ended up being a nightmare of design as a result, where mediocre or even awful PrCs had extensive and painful requirements, while extremely powerful options might have no more than "take a naughty word feat and pay some guild dues now and then." The meta-aesthetic value of "these things look like something that requires special training" resulted in flat-out BAD game design, even though the underlying idea--taking a small, focused "alternate class" for a few levels--was sound and interesting.
Paragon Paths, by comparison, were extremely easy to qualify for (rarely having more than 1-2 requirements, many of which you could meet by taking a single multiclass feat), were structured so as to give benefits within a consistent overall power level even if individual options were still stronger or weaker, and did not prioritize having the look and feel of something you had to "work for" in order to enter. PPs were this specialization process done right, not massively over-valuing the meta-aesthetic considerations of the concept. PPs focused on ensuring that the overall play experience happened as intended, and not on ensuring that the mechanics for a thing looked like they "should be" mechanics for that thing.
And yes, you're right that this is not something that can be easily assigned to either design philosophy or specific rules. It leans closer to the former, but it's also "practical" in the sense that it gets really hung up on the specific pieces used for achieving one's ends. Digging a little deeper on that: There are (at least) three values one can have when designing a game. One can value effectiveness, asking, "Does this game achieve the experience I designed it for?" One can value message, asking, "Does this game communicate to the player the messages I want to send?" (Consider Monopoly for an almost exclusively message-centric game.) Or one can value these "meta-aesthetics" I'm talking about, asking, "Do the rules of this game have a pleasing appearance and structure?"
I'm asserting that "a pleasing appearance and structure"--such as, for example, 3.x's skill point system, which feels like a great way to handle skills but tends to be super punishing to anyone who likes variety or playing against type--has become a dominant or even hegemonic goal for many in design-discussion places (such as this forum).