mhm essense warper is pretty good balanced shape. It does not feels overpowered. You can get a lot with them. But fusions usually do not really something feels necessary considering you can edit stuff. But essense ripping and and species change require a random item. Which is kinda overshadowed with body exchange. Can take interesting essense character and just put into any captured body of race. I guess a bit slower because need retrain new body. But considering how hard to find race change items it feels good trade off.
I just feel all those transformation classes you get just makes a lot of rewards uninteresting. Like you can get those incarnations and souls... why bother unless you need some race you just can get at river of souls. So it becomes kinda redundant to hunt anywhere else for souls. (even if they have unique traits.) Maybe for knowledge if certain realms and assignments more likely give you some different knowledge, like builders and architectors, or warriors. But even then.
Same goes for energy and matter. Ok it is good to have few assignments here and there. Fairy tail realms having fate income assignments... now I felt it would be a theme and it is cool. You go to all places where miracles fated to happen, and kinda twist fate in your favor. Thought there would be more of that sort. Especially quite few assignments revolve around literally ruining fate of the realm.
Speaking of realm shaper soul power here is little idea. Dynamic realms including your own. Could be something simple as set of tags that might happen depending on what assignments you do in realm. Realm shaper allows to fix things back, or shift realm assignment probabilities in favor if you spawn task with them.
Up to shifting certain balance and adding some assignments based on one or another but again might be too hard to come up with fun assignments for this.
But so many fun things, what happens if you do happen to bring demon candy curse on river of souls. Or heaven vs hell balance. Or conspire with scientists and bring certain "relics" to other real maybe fairy tale real to make them seal those and add few assignments as they go over zealously to seal forbidden knowledge that ruins their realm.But again that one sounds too big goals to do. But even something simple as changing odds maybe assignment or two may appear. Or some assignments become more or less rewarding or souls/incarnations gain certain traits now coming from certain assignments.