Since I stan most of the groups who have more than 7 plus members, four seems less. Exception is Blackpink, a very well rounded group and thinking of even adding members sounds ew (debut).
For me Aespa also seems well rounded after Forever got released. Every member has a distinct voice and can uplift any song. But there are clear signs of them adding one member. With evo-evolution scene containing 5 people (one bg model and aespa) and particular emphasis at the end of a person yeeting out. Also I am a pre-debut fan and there were so many faces shown with their talented videos, especially Helen. I will keep up with adding members propaganda till next comeback.