It's not a team effort when someone never even shows up for the huddle. The only credit I can give Hydaelyn was shielding WoL against Ultima at the end of 2.0 and then blasting Lahabrea, and ultimately his design was to weaken Hydaelyn rather than cause a Calamity so by expending all that power she arguably did what he wanted anyway. Aside from that her best showing was sending Minfilia to the First, and it's debatable how much of that was by her own power. Every other instance of WoL saving the world was down to WoL themselves, and as people are so fond of pointing out in relation to the tempering argument WoL would always be doing that with or without Hydaelyn's blessing. And as an aside most of what you reference on this front weren't shaped up to be Calamities.
The issue is we have no evidence for previous Warriors of Light ever stopping any Calamities. Historically they're known to appear on the eve of an Umbral Era, which implicitly suggests that they have a very low success rate. Even the instances where we know they've done heroic things, such as with Tenzen or Ramza, we neither know if those situations would have developed into Calamities (as Ascian involvement looks to have been zero), nor to what degree Hydaelyn was even involved.And there's also an uncountable factor: you don't know how many Calamities that previous people with the Blessing of Light stopped. Since there's no evidence Hydaelyn started picking people recently, and we know of heroes in ages past, it's only natural to assume there were 'Team Hydaelyn' people in previous eras.
Maybe it was an accident, but as it is there is surely more evidence that it wasn't. Not to mention she's shown a very strong motivation to keep the cosmic dynamics as they are now, what with the great dimensional barrier and the Warriors of Light and everything. And as Vyrerus pointed out, if you look at what this state of being is responsible for and conclude that it is unjust, then Hydaelyn is responsible for perpetuating no small amount of suffering herself.We know she smashed the Ancient world, but personally, I very much doubt that it was intentional, because nothing we've seen has ever suggested a desire to.