2023 opinion
We don't know much about Theo, but I picture him as a sensitive, smart, rebellious, and shy. Going off of these traits, they'd be terrible together. Hermione is also sensitive, but she'd still get annoyed at his sensitivity because she can be contradicting like that. I also think she'd be frustrated with his flirting. I think they'd be good friends, though, especially in a Drarry fic, because their intellect and love of learning would match one another's. They'd bond over magical theory and spell work. So...I see it more as a bromance than a romance.
Rating: 3/10.