I tend to try to limit my usage of "aether" as an explanation to situations that involve what aether is presented to be used for - magic and magical effects. Black Magic, White Magic, Arcanima, Summoning... all of that is easily pointed to as using aether.
In the MNK story quest, unlocked chakras are also tentatively linked to aether through the quest-giver. So, a lot of the superhuman aspects of MNKs I can explain away as tapping into one's one aether. Inner Beast could possibly fall under this. By extension, you could also consider any great feats of strength to either training or using one's natural aetheric resources (possibly one allowing you to do the other!)
What I try to avoid doing is using aether as the stopgap reasoning for things in place of a more thought out solution. If it can be reasonably explained with aether, that's fine. Using aether as the equivalent of a shrug, though, not so much.
In the MNK story quest, unlocked chakras are also tentatively linked to aether through the quest-giver. So, a lot of the superhuman aspects of MNKs I can explain away as tapping into one's one aether. Inner Beast could possibly fall under this. By extension, you could also consider any great feats of strength to either training or using one's natural aetheric resources (possibly one allowing you to do the other!)
What I try to avoid doing is using aether as the stopgap reasoning for things in place of a more thought out solution. If it can be reasonably explained with aether, that's fine. Using aether as the equivalent of a shrug, though, not so much.