For me theme and art are important but overall fun gameplay and rules are more important.
I was thinking how I don’t love Iron Maiden music. I had never really listened to Maiden so I thought maybe I just never gave them a chance. So lately I’ve looked their top songs on YouTube and if they come on the radio I let the song play instead of instantly changing. But they just don’t do it for me. So I was thinking if I could buy a Maiden in spite of the theme? I would say yes because the art is good, the music is not my cup of tea but I think I could tolerate it.
In the past I didn’t want to buy AcDc because I thought the art was bad but otherwise everything else was great so I did buy it. Just got around to change the translight art which I far prefer.
So my answer would be that in most cases I would buy something with bad art or theme. I’m sure if there was ever a horrible theme like say Backstreet Boys pin that would probably never buy but 98% of themes I think would be ok.