This is a perfectly valid option and I can understand that. However, to each his own, your 'wants' is only a straw in a big haystack.
Some wants to play it from a more competitive standpoint and I have to say, all the power to them, as all the power to you. As long as an option, in this case dual-spec, does not hurt other's experience, I don't see any valid reason why it can't be done / implemented.
Also, in the long run, these kind of imbalances will hurt the game overall, because it creates a disparity in the game's class distribution and it will be more and more harder to fix as time goes by. So I think we all have an interest in creating a healthy class base, where every option has something to offer and does not get invalidated by it's peer options almost completely.