If you stop and think for a moment, those two are together. It has nothing to do with game balance and all about reducing the number of special actions that have to be processed which is currently resulting in some central game system choking out. That means Mr ProcsAlot and his guild of ProcMasters running VoD/THTH/PN/Dryad/Baba/ect all with debuff weapons will lag an entire set of servers out, not one instance, not one game world, no everything that happens to be running on that piece of hardware gets turned into a slideshow for however long it takes them to finish the fight.
That is why you can be a level 3 running some harbor quest solo and suddenly lag and stuttering out of nowhere. It's not you, it's not your server, it's some guild somewhere running a raid with a ton of LGS weapons and other various other abilities and traits that do improved destruction / vulnerability / ect. Just press "Z" while targeting a raid boss and watch the ridiculous number of things that keep cycling.
Is this crappy design? Most certainly, apparently it's been around since the game was created. Changing it would likely require some platform redesign and changing base code, which might not be something they want to fund for such an older game.