Don’t know if you can really claim any credit for the design of Arbustodon. The monster is dead weight besides raw man eater, whereas Leogeist is excellent if left alone.
The Leogeist buff idea I used to suggest years ago was changing lifeflip into “crescendo boost” which is 50TU and gives a double charge and small heal. The idea being, it can charge crescendo faster by not attacking. I think I still stand by that. Lifeflip is a weird move to have on the monster and it’s got the lowest attack stat of crescendo legendaries so this fits pretty well I reckon.