I don't mind having only one spec. But I can understand how it can be annoying for those who want to diversify their experience. I really thought I had heard it would be implemented. Maybe just one of those rumors ...
A friend of mine keeps his tank spec in pvp and he's very useful in warzones that way (and not just hutt ball). It's a different way of playing. You don't go for the kill with that spec but you're a real asset nonetheless.