1a it fairly easy to get a spirit essence. not to mention there is almost no need for them on that server. 35 cleric needs one for level 36(so never?), 31+ mage needs one for recall(1 per mage user, next to never?), and then soe craft. (ive seen soes sell for as low 450k on 1a so obviously not a big deal.)
on main, a soe is a bit more dynamic and impacting. i can see why an ectoplasm build up craft would be nice. "go kill banshee" is hardly a good solution.
the craft u suggested is much too short imo.
maybe lengthen it a bit
5x ectoplasm and a mana water= brew 1
mana core+blue ether= brew 2
3x brew 1 + brew 2 = brew 3
brew 3 + orc's granite+hades amulet = spirit essence
maybe something more inline like this.