Furthermore, it's not clear that "seniority" would trump "skill" in a co-op, either. Or that the opposite is true of a more "traditional" workplace.
The job of each worker-owner is, in part, to help other worker owners developer their strengths to their fullest for the benefit of co-op.
An employee-owned co-operative corporation (EOCC) governs as form of direct democracy. In my experience, your biggest obstacle is going to be collective decision-making. How well you do that is a test of the people in the co-op. Consider: management is just another skill, not a rank. You don't have a boss. You have people who are counting on you. Management serves at the pleasure of the worker-owners.
Unless everyone can make equally large payments on behalf of the company, you most certainly have bosses.
Find those people. They are the bosses. Everything else is theatre.
- relevant prior experience (before joining the coop) - longevity (aka seniority) - dependent care responsibilities - membership (a small raise once you become a member)
The prior experience piece is determined with a points system, designed to take as much of the self-advocacy (with all of its race/gender/class pitfalls) out of the process as possible.
The system also includes annual cost of living adjustments.