I don't understand Occulus quite yet. He has an ability that is supposed to give nearby allies a chance to inflict lightning damage. If it affects minions then I think you need to view that skill as a supplement to Ball Lightning the way coven, conversion aura, entourage, etc. are necessary for their respective casters' minions.
However, if that ability does not affect minions, then Ball Lightning is just awful until level 15 when it becomes ridiculously powerful for all the wrong reasons. Regardless I don't think it makes sense to play Occ the way you do other generals no matter how the minions work. They're not persistent creatures that you can spawn for free or keep from fight to fight. You need mana for them and Occy also has what is probably the best ranged nuke in the game, allowing him to affect a fight without actively engaging in it.
That being said, I don't think the morale builds are a good way to play any DG, so perhaps I'm mistaken. He's still quite new, though in my limited experience with the orbs they seem inferior to whatever else you could take.