I like all of these changes, and something I want to add to Earthly Star as it currently exists:

Earthly Star is considered a bar-buff. When the first stage buff fully counts down, it gets the second stage. Because of this, it actually has bad compatibility with another one of AST's very powerful tools: Celestial Opposition. If you use CO during the first stage buff, you're actually delaying the secondary buff by 10s. If it was changed to being a function of the gauge, then this problem would no longer exist.

Minor thing, but I would like to see the damage come up slightly, and the target ring be the actual size of the used effect.