I like hearing groups with more than 6 members and I realised it's because the bigger variety of voices just makes their songs sound so colourful in a way?
I do listen to songs of groups with 6 members or lesser though but songs with more than 6 voices just stands out better to me + there's more different ways to mix and match different voice types(?) in different segments of the songs, which makes it more interesting to hear (p.s: even if it's multiple short parts or adlibs, as long as it's cohesive with the longer parts of the songs).
I think it's the main reason I liked hearing survival show groups like Wanna One (11), IZ°ONE (12), X1 (11) etc and my favourite group Cravity (9).
I'll probably look out for Boys Planet debut group too since they'll be a large group like Kep1er (though the exact number is not yet confirmed) and a lot of the trainees have shown to have good vocals.