I like this idea, but there are some flaws in it...
- The Job Events shouldn't use jobs normally found within iEra as certain players I know would practice until they're good enough to "hog" the events. They should be different jobs designed specifically for the events. Since you're the one who brought up the idea, I'll let you decide.
- The time you picked for the event, in my opinion, is too long. It should be 20 minutes at most.