I don't think we can consider them as "buffs" because a buff is when you give an empowerment and the ability becomes stronger.
Most of the changes are just a rebalancing. How AST should have been when it came out.
It's clear that the Dev Team fears that AST can become OP but the fact is that the other two healers are already OP.
Anyway, I really appreciated the changes of Sinastry that now looks like a "buff" and not only an utility, Disable and Collective Unconscious.
I would have appreciated something more for Celestial Opposition.
AST is not stronger then the other healers, but just acceptable. I'm sorry for not being enthusiast, but this job really disappointed me a lot and I just don't get why the dev team was so generous with Scholars and White Mages and so worried about AST being OP.