The reformist vs. revolutionary debate is well hashed out in many places, and as you say is hard to evaluate outside of context-specific situations (is attending columbia law but refusing to play the grading game fighting within the system, or is revolutionary compared to getting the grades and fighting the system as a law partner?). But I find the violence vs non-violence distinction slightly more interesting, particularly in our media age where one person choosing to set themselves on fire can achieve far greater social impact than a guerilla group with guns. On the other hand, depending on your view of responsibility, one may be seen as contributing to violence by the mere act of remaining silent when it is committed by the system of which one is a part, so the distinction probably falls at some point there as well.

I also share your concern about co-option, although am perhaps less concerned about OWS being net bad than you. I'm not sure about the idea that the lower risk of co-option path is always better, even if such a thing were possible to evaluate. Someone has to run for president in our current system, despite it having huge risks (certainties?) of co-option to a large degree. If everyone who was truly committed to avoiding the risk of co-option avoided such positions, then until there was a sufficiently critical mass to replace the existing system, the only people left running for such positions would be those who would be far more comfortable with co-option, or at the least ignorant of its occurrence.