I put that there way back at moria release; it was when spiders got their daze. Up until that point in the game, freeps had never actually experienced long duration (15 second) grey bar.
It's become more ironic for me to keep it as time has gone by; arguably spider CC is as powerful as loremaster (if only a little lacking in the AOE department) nowadays. If SOP:R ever went away, they might honestly have to look at spider CC for some cooldown changes/nerfs.
If you were to ever write it, I'd like your take on the mechanics and sets the spider class has available which would be deemed as ridiculous in specified situations. Considering your seemingly natural objectivity, I'd find it quite interesting what you'd have to say on the topic.