Celestia and Luna versus a cloud: Post-match analysis · 4:33pm Apr 11th, 2016
On the one hoof, Celestia and Luna are the closest thing Equestria has to gods. They control the sun, the moon, and the stars; they're thousands of years old and still in their prime; they're capable of magical feats beyond any unicorn. The only beings who've ever fought either of them to a standstill are each other, Discord, Chrysalis (beefed up on more love than she'd ever known before), and the Smooze (who, under the circumstances, we can file under Discord). What they fought couldn't have been a mere storm; rather, it was the land itself trying to destroy the Crystal Empire. For all that they help the natural cycles along - managing the weather, keeping the seasons in the right order, helping birds and breezies to migrate - Equestria hates pony civilisation. As long as they stay in their own environment, ponies are tolerated - but a city in the Frozen North will have Nature constantly poking at its borders looking for weaknesses.
On the other hoof, alicorns - though stronger than any other pony - are not actually divine. They're born, they grow up, and in the end they're as mortal as anypony else. Raising the Sun is impressive - but it was something a team of trained unicorns could also do. Ditto dreamwalking. Celestia and Luna may be unmatched in their wisdom and experience, and stronger than any single being on the planet. But they're not omnipotent. And the only reason they ever appeared so was because we were seeing them through Twilight's eyes - a younger Twilight who was more blinded by hero-worship than the present one. After all, when you're a child, your parents seem impossibly wise and powerful. But as you grow up, you become disillusioned with them, and eventually you become an adult yourself. That's Twilight's journey, and it's why the alicorns seem much weaker today than they did in Season One.
On the third hoof, clouds are scary. Don't let their fluffy appearance fool you - even the smallest is a mile-wide roiling vortex of ice-cold water. Anyone who's been through a storm in a light aircraft or boat knows the danger they present. With any luck, your pants were already wet from the rain so nobody noticed. To maintain one's calm in that situation - never mind psych oneself up to fight through the storm, pegasus magic or no pegasus magic - takes a lot of willpower. Celestia and Luna's contribution may not have won the battle, but you can't begrudge them points for effort.
On the fourth hoof, the writers knew what they were doing putting them in that episode. Cadence and Twilight know when they're in over their heads, and would have called Celestia and Luna to ask about alicorn babies even if they weren't already anxious to meet their new grand-niece. It would have been more of a stretch to write them out entirely than to add a crisis for them to react to. And finally, what kind of a season opener would it be with no Celestia?
I had a point I was making, but I forgot it.
Ok, so I really need to hurry the hell up and watch Season 6, eh?
3865101 Hope I didn't spoil it for you too badly