I would say if the series focused on the teacher route instead, I think they can probably pull it off where you won't think it's too weird.I knew people would comment about the teacher xD Honestly it reminds me of Oregairu somewhat since the teacher route actually exists... (though personally I love the anime for treating the teacher as his guidance counselor and not his lover.. it's too weird...)
Yeah it'd definitely be less weird in this case because their age gap is a lot closer with Kaizaki's real age. (I was specifically speaking in Oregairu since Hachiman is a teenager and teacher is you know.. an adult)I would say if the series focused on the teacher route instead, I think they can probably pull it off where you won't think it's too weird.