I always took "Role playing" completely differently.
I'm not trying to fill a pre-defined slot in a team. I'm playing a role, like a character in a play. It has nothing to do with being a good fighter, cleric, wizard, monk, druid, rogue or ranger. It has to do with being a colorful and interesting character.
I've also take a different view of what constitutes "power gaming". It isn't about synergy or clever design. It's playing to maximize the total power of your character. Acquisition of power becomes the goal, and the more power your character has, the more "points" you rack up. It's about "winning", in the worst sense of the term.
I often find these two concepts to be incompatible in play. Most (not all, but most) of the power gamers I've encounters use character personality only as a tool towards the acquisition of power. They'll have a character backstory that's engineered simply to justify their power build, frequently as a bid for (you guessed it) more power.
"Daddy was a pirate and mommy was a unicorn and I was born on the third full moon of the month..." kind of stuff makes me want to vomit.
(In case you haven't caught on, I really don't like playing with this type of player. The arms race that the game inevitably turn into kills a lot of the fun for me.)
So, by all means, become proficient in character design, learn and understand how the various feats and PRCs combine. But use this knowledge wisely, as a way to bring your characters to life, to lend color not merely to your creations but to the world they live in.