If you are hanging out for a free spec in the coming 2.1 patch... don't hold your breath.
We only give free respecs in cases where the shape of a tree changes, meaning actual talent placement and/or point cost. Meaning if a talent changes names and effect, but retains its position and point cost it doesn't warrant a free respec.
(edit - I think my initial paragraph was a bit vague in what in relates to, and that's the changing shape/point in relation to breaking builds. My next post clarifies a bit more: http://forums.worldofwarcraft.com/thread.html?topicId=98642215&postId=985641050&sid=1#54 The below paragraph does go into the actual issue. I'm not sure if most people skipped it or just took the first paragraph out separately as the main statement, I'm sure I would too.)
The reason being if you were to spend 5 talent points on a talent that was then reduced to 3 points, you would me missing 2 points which you could have spent elsewhere. On the opposite end if we were to say put in a new pre-requisite for a talent you already have, you would have more points to spend elsewhere than you're intended to. Or the possibility of any number of unknown side effects.
There aren't any free respecs in 2.1 for any classes, unless of course some new changes were to go in that required it before the release of the patch. At current though none of the changes being made would result in one.
