WvW Scourge Question

As someone who doesn't play much WvW, but is probably staring down the barrel of the same nerf gun, what exactly makes Scourge in WvW so objectionable (or appealing, depending on how you look at it)? Is it the size of the area they can cover with AoEs, or the target cap on their shade skills? Is it the conditions they inflict, or the boon corrupting, or barrier? Some combination of these things?

Just curious how exactly my PvE Scourge is going to get neutered.

AE boon hate. And combined with other scourges the conditions they can put out.

Barrier is a nice to have but if it was gone, still everybody would play scourge in wvw