So what we know about Celestial opposition is that it is going to be akin to stance dancing, and some are confused to what it means so the following is what I think its going to be -

Imagine you are in a raid and everyone is topped up in health and your healing partner is able to solo heal, normally this is the part where someone pops cleric stance dropping your healing for more dps but instead the Astrologian pops an aoe balance or arrow and then goes into celestial opposition.

They become a "totem" where everyone in range of celestial opposition has their buffs placed by the astrologian "time stop"ped as a support class this could be a massive boon and its balanced by the fact that while you are effectively permanently placing a buff on a group you can't heal or move to dodge.

This is all of course speculation but it seems like it could work and would give the skill more of a "big deal level 60 skill" feel compared to how it currently is.