@Background Pony #A080  
The romance may be generic, but what this arc is doing is actually giving us character to Celestia, something the show has consistently avoided, and what leads people to want to call her Trollestia or the like.
 
Having a better idea of what her youth/earlier days were like is extremely valuable for those interested in world building. I would argue fairly that pulling alt-Sombra out as the love interest might be a bit lazy but works just fine for a story that is meant to world-build.

@FanOfMostEverything  
Why make a “mirror universe” character out of a character who literally had no personality whatsoever and ended up being nothing but a plot device? And then make his entire character revolve around a tepid, generic romance?

@Background Pony #A080  
You don’t seem to understand the whole “mirror universe” concept.

@Background Pony #FB68  
So it really is a completely different character.
 
What was even the point of making it Sombra?

@Villain Pony  
Star Swirl said it when they met Sombra for first time. In the comic, Celestia said that she began seeing Sombra alone after Luna was gone, and Evil Sombra was defeated by Celestia and Luna.  
So at this point of the story, Celestia and Luna have already defeated Evil Sombra and Celestia banished Luna to the moon.

@Background Pony #FB68  
No Starswirl said that there might be a Sombra and that he might be evil. So this is before King Sombra and Nightmare Moon.

@Background Pony #A080  
He doesn’t became a villain.  
Actually, Celestia and Luna have already defeated Evil Sombra at this point.

Putting her subjects needs and safety before her own desires since whatever pony year this is.  
Celestia for president empress of the universe.

@Background Pony #A080  
Gee, that doesn’t sound familiar at all.

@Background Pony #3C6A  
^Exactly. Who wouldn’t go looking for love and adoration at that time in their life?

If destiny and fate can screw others, then it can do the same to you.

@Background Pony #3C6A  
For a dude.
 
A really boring dude she just met.
 
Who becomes a really boring villain.

She’s only human - er, well, you get the point. Not to mention her own sister went nuts around this time, showing the fallibility of the goddesses and underlining Celestia’s loneliness.

“Starswirl said I’m endangering the lives of both universes (and possibly unraveling the fabric of reality). GOTTA SEE DAT STALLION!!!!”  
-Celestia Responsibility Pie, IDW comics, 2014

Volume I, no less. I can only imagine how many more there were after that. Makes me wonder how well “crazy old unicorn wizard” advice can hand crazy young earth pony bakers…