Item/quest nomenclature usually hints toward some aspect of future content. What could feasibly be untouched yet so powerful that it poses a threat to us?
The "Void" Shard
Literally ANY Unexplored Space Area
Multiverse/Parallel Universe threats
Also take into account that where Zodiark is "gone", his sundered pieces likely aren't. He still exists on other shards. Additionally, with Hydaelyn gone, who's to say that her blessing hasn't been protecting us from something that couldn't find us/approach us before but can now? With the shards still unjoined, what threat would it cause to have more calamities in a time without Hydaelyn or Zodiark, for that matter?
Narrative-wise, there's plenty of unexplored possibility that could necessitate our power as it is now. BUT, I still think it's possible to do content with a power reset. Just think of a world where we're no longer able to depend on aether, or a world where we're forced to exist as an alternate version of ourselves that isn't as powerful.
Additionally, the entire Underworld in this game was literally exposed and is chock full of aetheric energy/power. Somebody down there will take advantage of that.