This is easy to explain.
High end content, they simply do not have enough of it. There development cycle is slow and its going to take them months to be able to sort out the abomination they have just released.
Everyone enjoyed PVP pre 1.2 sure a few tweaks were needed hear and there but not to the level we just had.
More will unsub over the coming weeks when they realise grinding for that extra bit of PVP gear is really not worth it and have better things to do.
Aside from those that like the SWTOR universe the rest will have migrated to bigger and better things very soon. AKA - Terra, GW2, TSW, LOLPLANES and a few indie titles that pop up now and then.