Apart from the dedicated PvPers, people who want merge could reroll easily. The ones who prefer action over triggered whining on forums did so weeks ago. Kinda sad to see people still whining over a merge as if they couldn't already be 60 and preraid BiS by now if they had any inclination. The high pop experience is there for you. Its called Elysium.
Merging ZK and all the players who prefer smaller pop will simply go back to other games. THe project will no longer be providing what they want. If you can't apprecaite that this game IS NOT FUN to people when overpopulated, thats fine, empathy is a developed skill. It doesn't make it less true because you can't fathom it though.
Dislaimer: People getting borked over by shrunken PvP brackets are about the only people who have a valid complaint.