This is where you can see the difference between EU players and US players. I agree with you about the cheaters, usually few in number, all know each other, and are basically a server known joke.
But the difference here it seems EU players have not given up on open world like US players have. Even on the PvP servers it's like you almost have to beg people for open world, and when it happens it lasts only minutes and after a few death's people just do other things. It was like that for years on Tyranny and it no different now, well know you have a small group of players who attack each other, the lame thing is that they all know each other and have no one else to pvp against.
Set, no world pvp. No one will even show up to defend against a siege but once in a while, and even then after a few deaths they just give up. There is no want for open world pvp at all. The only thing is that minis pop non stop, sometimes 3 and 4 going at once and multiple sags back to back.
But US players flocking to PvP servers? It could only happen with a merge and then I think players would be cautious of risking their ability of farming T4 and whatever new high end content comes out (if any). Very few of us even care about open world anymore...but if the PvP server population seemed viable and content could be cleared I bet a few months after the merge people would start to make their way back.