That design philosophy was in 3e. It was called system mastery and is basically found in Magic the Gathering as well. The basic premise is that those with the most rules knowledge gain the most from the rules by being able to create combos that are more powerful than the average player can figure out.
This is 4e though. The design philosophy mentioned above was actually one of the things the designers spoke out against in the early days when they were talking about the decisions for a new edition, and was one of the reasons for making the game more open and transparent with the math behind the mechanics.
It's probably a lot more accurate to say that "system mastery" is how the marketers of 4th edition decided to tell the designers to retroactively characterize the 3.x design philosophy. The designers fed us a lot of nonsense that no thinking person has any business believing in the early days of the runup to 4th edition.
Anyone remember how characters were going to be defined by their class abilities and items wouldn't matter much? They would basically be flavor. One book after the 4th edition core books, everyone was running around with iron armbands of power reckless and bloodclaw (or subtle) weapons and off-hand staffs of ruin. Yeah, they delivered on that one.
How about there no longer being bad powers? Compare careful attack to twin strike some time. Or Turning Point to inspiring war cry. Or Forward Observer to guileful switch. Or for a resourceful warlord, war of attrition to stirring force. (For an inspiring warlord, you want to compare phalanx assault to war of attrition). It seems like there are proportionally as many bad powers in 4th edition as there were bad spells in 3.x. Another instance of hype delivered... not.
Now, if you want to discuss system mastery as putting together combos... well, that might as well be the whole point of 4th edition. Putting together a combo of powers that do more together than they would individually is
the key skill of 4th edition play. What's more, while in 3.x you could buy off that bandwagon by playing a barbarian, making the obvious choices and doing your job pretty much as well as any other barbarian, 4th edition offers no escape from system mastery. The barbarian, as much as any other class has to select his powers to work together and use them synergisticly.
So, it may be that designing deliberately overpowered spells and feats was a WotC marketing choice designed to sell more books. (Presumably to 3.x players of clerics and druids and to 4th edition fans of Str/Con fighters and barbarians). If so, there is no reason to believe it other than the self-congratulatory pre-release posts of a bunch of designers with a financial interest in making you believe 3.x was unplayable but 4th edition would be perfect. 4th edition carries the exact same features that were supposed to be a hallmark of that philosophy.