I'm not ready to bury the generation that turned me into a hardcore Kpop stan (and MMM fan for life), but we're clearly in the middle of a major generation shift in the GG space.
So when it's all said and done, how will you remember the queens of the third generation?
For me, it's the distinct, contrasting style of each group.
Especially for the original big 5 wall:
Red Velvet, MAMAMOO, Twice, BlackPink and Gfriend had VASTLY different but very distinct sounds as groups.
Generally the moment a song started for any of these groups (and to this day minus GFRIEND RIP), you knew right away which group it was without even checking.
The groups didn't chase trends. They just did their own thing and did it sublime 
