I did say they need main characters for bigger threats, but I still think they should have been able to take the Changelings. For one thing, there had been a threat and everyone was on high alert. Did they think the force field was all the protection they’d need? A good strategist would have a backup plan. And when a third of the population, as well as gryphons and dragons, can fly, it’s common sense to keep an eye on the sky.

Well, you have to imagine that they weren’t exactly prepared for the attack they were expecting to come from straight up with less then 30 seconds warning thanks to their forcefield suddenly failing due to an inside job. Said inside job because of a powerful shapeshifter from a species nopony knew existed.
 
So, they had to deal with the vengeful goddess of darkness (whom everypony thought was just a children’s story) appearing with literally no warning, an omnipotent (and silly) reality warper unexpectedly breaching containment, and what I mentioned above.
 
I don’t exactly blame them for looking useless.
 
The Wonderbolts’ uselessness against Spike was kinda ridiculous, though.

And the Wonderbolts aren’t better by much. In the fight against Spike, they hit him with the equivelent of a hair cut before he kicked their collective asses, and they got beat up by Rarity ON ACCIDENT!
 
And to top it all off, they still haven’t made Rainbow Dash a member, despite the fact she is seemingly better then all of them together. If anything, the Wonderbolts should look up to HER.

Well untill we see them in action doing SOMETHING we can assume they are totally useless.
 
Hell apparently the wonderbolts being the local stunt flyers are considered a better fighting force then the actual guards.  
Now that’s just sad.

That moment when you realize the elite fighting force you put your blood, sweat and tears into are STILL incompetent Redshirts who exist to be killed by the dozen, and your geeky librarian little sister could probably outfight you.
 
Though to be fair, the Royal Guard isn’t completely incompetent. I’d compare them to UNIT: They can handle the day to day stuff just fine, but need main characters to resolve anything above a pickpocket.

Cadance:“Buttsex”

Aw, you found out. I just wanted to see how everyone would react.

Poor guy got antsy the previous night. Ate all sortsa junk.

*farted*

This is from the wedding.
 
Twilight just barged in accusing Cadence.

I believe this is a very quick shot from one of the previews, yes

This is from the preview? it looks like it’s from the wedding.