Unfortunately it has been established that distribution though bit-torrent is not viable, please stop asking, use search feature on forums; THANK YOU have a great day!
As for the hosting sites.. well, it's in the hands of the authors first and foremost. the individual authors decide where to host their own addons. End of Story, you as the end user have no right and no place in this regard. Curse.com, ui.worldofwar.net, wowinterface.com do not choose what authors are hosted there but the authors for the most part choose. So before you start crucifying curse.com for being the badguys, they really are not to blame.
As for the curse client... there are other threads to answer your problem.