You have a point there.
I think we could safely cut those bonuses off of Bath House/Hammam and Hotel/Vacation Resort to start.
I think we could also increase Opera House from +1 happy/20% culture to +1/10%, but then completely remove the culture happiness from Movie Theatre, Red Curtains Theatre, and Holotheatre. By the time Movie Theatre comes around, Opera House has replaced Theatre so it wouldn't be a drawback if Movie Theatre didn't have a cultural happy bonus.
That leaves you with, over cultural spending in BTS, Brothel (+1/25%), Opera House (additional +1/20%), and Convention Center (+1/20%), plus some National Wonders (Amusement Park, National Sports League, Orbital Hotel) that only affect one city. I don't know how high most players take the cultural slider; I rarely touch it myself. At 50% culture, this would add up to +6 happiness.