well, rather than just getting rid of the Drop Your STR to Zero PDQ, try replacing the strands effect with "Fatigue". First failed save makes the PC fatiged, second failed save makes them Exhausted. Won't negate the victim in the fight, but still puts the lone victim of a roper in a bad situation. that still leaves the issue that the casters will sit there and suck due to the SR 30, electricity immunity, 10 cold resist. Though Fire orbs and Alchemist fire specialist will clean its clock.
Fatigued
A fatigued character can neither run nor charge and takes a -2 penalty to Strength and Dexterity. Doing anything that would normally cause fatigue causes the fatigued character to become exhausted. After 8 hours of complete rest, fatigued characters are no longer fatigued.
Exhausted
An exhausted character moves at half speed and takes a -6 penalty to Strength and Dexterity. After 1 hour of complete rest, an exhausted character becomes fatigued. A fatigued character becomes exhausted by doing something else that would normally cause fatigue.