A spec for leveling and a spec for endgame

This post by Catherine on WoW Ladies

(about getting just the right spec for PvP and grinding) got me thinking about specs and their purpose in general. For a lot of classes, it's pretty much accepted at this point that you spec one way for leveling, another way for endgame, and a third way for PvP. While some classes can pull off all three with pretty much any spec (hunters and warlocks, ahem), other classes are much more confined (leveling as a resto shaman or prot warrior is possible, but I wouldn't want to do it any time soon).

Is this a good thing or a bad thing? Blizzard has made a big deal (and a lot of money) about making sure that almost any class can jump into any situation at any time and do what they want to do. But the opposing viewpoint of that is that when all classes can do everything, no one class can do one thing better than others.

I think there's a good balance at this point, and though respec costs could be lower, they're definitely low enough that you can change spec a few times in the journey from 1-70 without a problem. But there are two ways to fall off the edge Blizzard is walking here: either specs become too limited, and you need to respec to do different things, or specs become too vanilla overall, and there's no reason at all to change anyway.