I think to some degree Japanese language naturally flows in groups of 5 and 7, that's one of the reasons this form of poetry developed. Just like English naturally flows into weak-strong patterns of 5 (iambic pentameter, like in Shakespeare verse). It's interesting how every language has their own style of poetry.
Senryu can be fun. I enjoy reading them in the paper when I get a newspaper. They sometimes remind me of dad jokes (oyaji gag) because they can be silly but funny.