Adding members has rarely been a good thing because people often don't react well to newcomers because they feel their groups are already established yet people rooted for this hoping some popular SM trainees would be added and that the group would hopefully have 8-10 members.
I always felt that aespa lacks literally nothing, every member can dance, sing and they a good stage presence and amazing visuals + Giselle's rapping is one of the best among newer groups so when people were rooting for new members I was always confused.
aespa is perfect as four.