In my opinion, managing people is the hardest job in running a business (or forum). It takes time to put the right people in the right positions. While some are quick to hire and fire, I find that the wrong person can do a lot of damage in a short amount of time and set you back a ways. I think you should consider a tiered system, where you have maybe two lieutenants who oversee the eight or so other admins. Maybe something similar for the moderators. If you think you are at risk for burn-out again, you should let your team do the work and you sit back and make sure they are staying true and not worry about you having to do admin duties.