let's ignore vivace because that comeback was random as hell
but now that alive is released, i can now see the direction lightsum is heading right now. they are currently doing a cute energetic teen crush with a hint of cool, chic and girl crush concept. it is so obvious that vanilla and alive is similar due to the post-chorus drop after the chorus. i personally think that it is clever of them to do that because it allows lightsum to highlight a different side of them depending on the members.
so far, it has been established that lightsum members have 2 different and contradicting vibe, which are,
cute → nayoung hina huiyeon yujeong
girl crush → sangah juhyeon chowon jian
this glaring contradicting vibe between the members would cause a clash if they continued doing a cute concept, therefore adding a post-chorus drop to highlight the girl crush members would help them balance out the members' vibe. the dance break also did their job on drawing a line between cute and girl crush. i know people are dying for sangah-juhyeon-chowon subunit, but please be patient, its literally only their 2nd comeback and 1st mini album.
hina, nayoung, huiyeon and yujeong THRIVE in cute concepts. its impossible to give them a girl crush concept since there are minors in the group, therefore cute concepts are the best shot for lightsum. they will probably follow twice's route after the maknae line are not minors anymore. juhyeon and sangah KILLED the dance break, and the dance line is did their job VERY well.
in conclusion, nayoung hina huiyeon yujeong would not fit girl crush, and sangah juhyeon jian chowon would not fit cute concept. at least for me, nayoung and jian are currently sitting on the borderline between the 2 concepts. therefore balancing both concept with vanilla and alive actually works for them. at least for me, they have finally established an identity that are very lightsum-like. their concept are cute, but the cool and chic members were also highlighted during the chorus and bridge drop. the vocal line and dance line also slapped hard. cube really need to add huiyeon to the dance line and yujeong to the vocal line.