I still have the waifu knowledge. It stays with us 4ever
Regarding Kaguya:
I've seen some Gintama eps, not a lot though.
She's definitely high tier though.
Funny, cute, amazing comedic scenes and some badass scenes (that come with the well known Gintama parody).
Being Gintama, she (and other characters) make some weird faces but that's normal xD
So veredict:
She's top tier waifu