The worst thing, I think, would have been someone in a raiding guild finding that they're getting bored or burned out with the raiding but really enjoying PVP lately, and feeling like they HAD to go to a PVP-talented guild in order to get the PVP-specific bonuses.

Or vice versa, a lifelong PVPer discovering that they really like raiding, who ended up leaving behind their PVP buddies to join a bunch of strangers because they happen to be a successful raiding guild.

These things already happen to some degree, and there's already enough stuff in the game that feels "mandatory" based on your play style (talents, glyphs, gems). Setting up a system where people would leave a guild because the new "guild definition" system says their current guild isn't the PERFECT fit for their personal play style would have been a huge step in the wrong direction.

I know I'm not the only one out there who could have said "Screw friendship" and gone to a more successful raiding guild a long time ago, downed harder bosses, gotten better loot, more achievements, blah blah effing blah. I have been with my guild for three years because they're simply awesome people and I love them. I've seen a ton of people whom I respected take the opposite, "sure you guys are nice, but what's in it for me?" route, and some of them I barely got to know, but some of them really had become friends, and my heart broke a little. Great people left because some other guild happened to be two bosses further in Ulduar that week and had some slick-talking guy in charge of recruiting, their new guild dominated all their time and penalized people for getting saved to anyone else's runs, and we never heard from them again.

That is why I fervently believe that anything Blizzard does that encourages guild-hopping is, and will always be, a tragic mistake. Look at professional sports. Once you've made free agency the norm, you don't ever get to go back.