It would be so nice if they ever showed her doing something, ANYTHING, remotely epic.
Twilight practically out right worships her (now) former mentor, and seems totally petrified to even remotely displease her.
Ether Celestia has a mean streak wider then a mile and everyone is afraid of even remotely crossing her wrong; or she is epic level magic and stuff and its like hanging out with Dr. Strange and Superman combined.
Considering that unless Luna is much stronger then her bigger, older sis, Celestia should be able to easily break the ground too by just stomping on it, as well as transform objects and weather control.
Also we know she is able to teleport and can cancel other peoples spells. (At least the ones Twilight is inclined to do).
Personally, I've always wondered just what kind of government arrangement do they have.
Is she like the Queen of England in that she is mostly just a figure head monarch, with a elected Prime Minister and such really running things?
Or is she like the way Japan used to treat their Emperor and conceder her an actual god with total power over all facets of government and law.
If I had a chose in the matter I would go with the former and stay as far away from the latter as possible.
It would certainly explain why she started her own school. (What else is she going to do, just have tea and cake all the time?).
Also, in imagining a RTS Computer Game which dealt with the 2 sisters and the Dark Age War; Celestia being a Epic Level Healer seemed like a really natural fit for her.
As someone who could do healing magic, (assuming that sort of thing is difficult to do), she would be a great asset in any fight.
Especially if she could Auto-Heal those in the immediate area around her, just by being there and just being herself.
If that was a default ability, (also imagined increases plant growth too), then why the military and the population in general would so respect and outright worship her would be a "well duuuu" obvious reason.
Healers have always been highly revered and tend to make others want to protect them.
And that's just in a passive, no aggressive mode. Her targeting a specific person could super heal, or harm.
Considering her Sign of Power is a Sun. Healing, knowledge and Light seem to be some of the more commonly associated things to it; So in Attack mode the picture above seems to fit nicely with the idea of Sun Power.
If she got cut off from others and does not have to worry about hurting anyone she is inclined to care about, crating a AOE centered on her, that hits with the power of, well the sun, seems a good fit for her.
While some type of range attacks might still get through, any Zerg Rush tactics will definitely fail.
I can just see the Changelings Drones popping as they get too close to her, with a entire black mass of the chitterling mob having a wake cut through them as she just slowly walks forward. (With AOE on she cant run or fly or use other powers so she can only move at walking speed).
And while it might be tempting to just send her straight at the enemy, she can still be hit with powerful enough range attacks and some creature types can survive long enough to get in at least one hit before going pop. So losing her means you lose the game, plus you don't risk you best healer in the game who can revive whole armies, just to take out some drones and a nest. (Unless you messed up, and that's all you really have left, put that's game play stuff).
OBTW. Luna was the engineer so her knack was fast building structures and repairing non-organics, with a lightning bolt attack that had some very small AOE splash damage, but was definitely a range attack that could do a lot of damage to a single target very fast. Her cool down was longer though, unless you deliberately set it to underpowered rather then overpower. (It had multiple fire modes you could toggle through, and a power level adjustment option. Higher Power = Greater Cost + Longer Cool Down). Also Luna's Forces where more magical constructs and the recently reanimated, so players could freely just trash them without feeling bad about it.
But Celestia would have to deal with actual people, so her healing and food growing ability's would come in very useful during the Dark Age.
And it would totally explain why people so adore her, and why Twilight is so freaked out she might remotely be disapproved of if she ever did anything remotely disappointing.