@Starswirl  
Well Luna was the one who wanted the fun Castle while Celestia got to have her traditional one in Canterlot sometime later. Though considering that Nightmare Moon also seems to be so drastically different with no real similarities to Luna (other than really the appearance), it’s possible that it’s just the alter ego doing as they please. It’s a whole lot of speculating really.

TL;DR  
I’m pretty sure its some kind of overanalising

That is some nice over-analysis. Them deciding to draw another soldier type is something that you should probably not over-interpret, especially since they really couldn’t change what they already did for Celestia without looking weird, and Nightmare Moon let them do something completely new…

It’s simple:  
Celestia has always used stallions as guards in forever. Since the first season. NMM’s guards however had to include the mane six for reasons and it would’ve just looked stupid to give a single mare the job among a bajillion of stallions. It’s a writing thing and not because NMM is better than Celestia in terms of leading her kingdom.  
Aside from that, Celestia is an alicorn and could probably use her guards more effectively if she actually joined a battle too, once and a while. But again, it’s genius writing that we have to thank for this.

@Background Pony #4658  
Interesting point.
 
Maybe that was another attempt at one-upping her older sister. She’s not even going to bother with the capital already there, she’s going to rebuild her old castle! She liked that one better anyway. It’s all gloomy and dark, not like that bright place in Canterlot. And she really loved it back when she was Luna.

What I really find strange about the NMM timeline that no one seems to ask is why the hell is she ruling in a castle that was in ruins only a year or so prior? Not only that but the castle is surrounded by a hostile environment with no room for any kind of a sizable populace in sight. When NMM took over it would have been logical that she would have taken over Canterlot castle renovated it and ruled from there. With everyone there acting pretty hostile too that timeline gives me a really big insane tyrannical ruler vibe where even those close to the ruler fear them.
 
I find it funny how so many people always assume the worst when it has to deal with Celestia and when its NMM/Luna people always seem to assume the best case scenario.

@kleptomage  
True, but given they also sell fake cures, they’re still snake oil merchants.
 
Let’s just agree that they are most certainly shady and amoral business ponies.

@Spiritus Arcane  
They have a cellar that could keep cider fresh for a while. After that they could ferment the cider and have hard cider to sell.
 
@CardStock  
Oh yeah. I forgot about that episode. My point still stands for The Super Cider Squeezy 6000 though.

Also, with regard to the argument in the comments
 

@kleptomage  
AH but their tonic was basically snake oil remember

@Starswirl  
Let’s see. Taking a hostage for selfish reasons. Risking the lives of everyone on a gamble. Hmm. Motives are clearly one of selfish and not, but the risks are one of maybe a single life compared to a genocide.
 
This brings to mind a moral dilemma. Let’s say there’s a city that has no crime, no pollution, no disease, little to no unemployment, a great economy and no famine. Now this is all made possibly by the suffering of ONE child. This child is kept in a dark, musty and cold room that’s barely big enough for him to stand in. He gets fed once a day of a single bread slice and less than a cup of water. He also beaten daily and must defecate in his own room. Now alleviating his suffering even a little could ruin the entire system that the city is thriving on. One must ask, are the needs of this one worth more than the needs of the many?
 
It’s not a perfect analogy for what you mentioned, however again, one life over an entire countries? Which is more valuable? Is it really better to go with a winner take all like Celestia does or would caution be a wiser approach especially if it puts less at risk?

@kleptomage  
To be fair, fresh apple cider like that has a short shelf life.

@CardStock  
I wouldn’t call the Flim Flam brothers snake oil merchants. The SSCS 6000 delivered what they claimed - it efficiently produced good cider until they turned off the quality control. Frankly, it’s the Apple family’s fault for giving the brothers an opening by being terrible at economics and then letting themselves be goaded into a bad deal. Apparently it never occurred to the Apples to make enough supply to meet demand before they started selling.

@Starswirl  
But again, she’s supposed to trust her no? Why didn’t she ever once question why Twilight might do that as it seemed out of character. And didn’t her friends also learn to take Twilight a bit more seriously sometimes that season? Lesson Zero? And how did SHE not notice anything amiss? I mean she is the one who made Cadance a princess, she knows how she behaves and from everything we know Cadance has never done what the fake did. Cadance is next to perfect, there’s never been an indication that such stress of a wedding, even her own, could bring out this ugly side. It made sense for Twilight’s friends to not know, but even Celestia and Shining had to have noticed SOMETHING. Cause it’s not like Shining was totally under control either yet.
 
Sure, it’s an assumption, one that stands up to what we see. You’d be assuming if you thought there was more to it of course but again, don’t you think it’s a bit odd to jump straight to the demands after that transformation? No fear? No concern? All business?

@Background Pony #5F98  

 
Putting a child in chains and threatening to harm him if his caretaker doesn’t give her something she wants purely for selfish reasons.
 
Are you sure you want to compare that to Celestia’s behaviour at the Gala?

@Corpse23  
Not the first time I heard that theory.
 
@Background Pony #5F98  
The part about her handling of Twilight has a point. Even so, the way she reacted to Twilight going crazy and driving the bride-to-be to tears was very even-handed.
 
The part about Luna, you are assuming. That has less evidence than Nightmare Moon favouring bat ponies over others in her guard.

@Starswirl  
Also, still doesn’t change the “smart yet tyrannical” vs “kind yet stupid” does it? And exactly how tyrannical are we talking? Sure the spell, but again, even if it was selfish do you think Celestia would just LET that sort of spell lay around? And Celestia invited Discord to the Gala for selfish reasons remember? Not that many were entertained or had fun either Gala we’ve seen, the only one who had fun was Celestia. So clearly she likes herself some mayhem.

@Starswirl  
Oh verily.
 
Truth is, we don’t really know enough about what the NMM timeline was like for anypony not directly serving her, so unless they revisit it at some point, we’ll never know. At least for the others they either looked at it long enough to show how it was bad, or it was readily apparent like the Discord or wasteland ones.
 
That said…I am of the opinion that Celestia has been losing her touch. Ever since Chrysalis game her a smackdown, her plans have been kinda…stupid.
 
Still, all said, would still honestly rather have her on the throne than someone who the jealousy level of a greek god.

@Starswirl  
Kindhearted, unwilling to apologize for any mistake and all mistakes are either swept under the rug or passed off as not that important, risky gambles that could cost countless lives and that were completely unnecessary, she was quick to scold Twilight for suspecting something was wrong but later praised her for what she reprimanded her for (again, ever apologized for), and given what we know allowed her younger sister to fall into darkness with no attempt to help but went straight for the scolding and telling her to just do her duty (never asked why or tried to compromise).
 
Yeah. Nothing but kind-hearted my ass.

celestia just wants some eye candy.

@Spiritus Arcane  
That, and willing to screw up the timeline for selfish wants. That’s kinda what Nightmare Moon intended to do with the spell. Does that count as egomaniacal?

@Background Pony #5F98  
Granted, it probably was the timeline that was best off of the ones we saw except maybe the Flim Flam brothers. Pollution sucks but we didn’t see anything else wrong so we have to assume it was business as usual otherwise

@Starswirl  
So, smart and tyrannical, or kind but stupid?

@kleptomage  
Well and we didn’t even see ALL the timelines. Twilight implied there were much more. But either way, with Flim and Flam, shady business men can amass a lot. I mean some of the richest people in the world are snake oil merchants…oh wait I mean faith healers and Evangelical preachers. Again though that was just one of them, Twilight implied there were more so we don’t really know.
 
And given that compared to the other timelines, Nightmare Moon’s wasn’t the worst, yet Twilight said that they got worse and worse as they went. So she could have been exaggerating. I mean it’s hard to see Nightmare Moon’s timeline as we saw being worse than the Crystal War.