lightsum has 2 problems that cube need to solve :
1) too many sub vocals
2) people saying there are 'filler members'
therefore by fixing their positions, people might take every members more seriously.
current positions : main vocal
changed positions : + rapper
chowon is a literal ace, she can sing, dance and rap if given more opportunities. however, her dancing skill is is not on the same level as the top 4, therefore giving it is reasonable for cube to not give her a 'lead dancer' position. adding a rapper position would highlight her diverse skills even more, but cube might not want that because we already have 2 members focusing on rap.
current positions : main vocal, lead dancer
changed positions : +fotg, + visual
nayoung would be an excellent fotg, her expressions are very on point and she has veeeeery likeable personality. giving her fotg position would make her popularity soar because her fancams are also usually high among other members. she deserved those main vocal and lead dancer positions, argue with the wall. i also dont understand why lightsum has no visual positions. nayoung is easily their top 3 visual along with sangah and hina.
current positions : leader, lead vocal, main dancer
changed positions : none
she has the most realistic position that reflect well on her skills. her strongest feature is her dance skill, which she deserves so much. there's not much to say about her because she deserves her current positions. she's also the longest cube trainee, therefore she deserves the leader position so much even if she isn't the eldest member
current positions : lead dancer, rapper
changed positions : main dancer, main rapper (?) + visual
sangah is obviously not the best rapper compared to soyeon, but she gets the job done. sangah has potential if she continued taking rap classes along with jian. also, sangah being a lead dancer is really questionable because she's evidently a main dancer material. even lead dancer nayoung didn't get as much dancing highlight during the stages unlike dancer duo sangah-juhyeon. its obvious that cube need to upgrade her position. also, adding her as a main dancer allows them to adding another member to the dance line, which are,
current positions : sub vocal
changed positions : + lead dancer
sangah is her biggest obstacle right now. sangah and huiyeon are on a different level, therefore removing sangah from the lead dancer position would allow people to stop comparing both girls. nayoung and huiyeon has similar dancing technique, therefore the gap is not as obvious as between huiyeon and sangah. she deserves more credit because dancing is her biggest feature right now. she also usually get the center time during post-chorus drop, which i think would really reflect on her new lead dancer position.
YUJEONG
current positions : sub vocal
changed positions : lead vocal wtf
cube is so stupid for putting her as a sub vocal because my girl can sing wtf. she's literally stable and always sing live during stages. yall should stop sleeping on her, even cube is sleeping peacefully on yujeong 
current positions : sub vocal, rapper, maknae
changed positions : + lead rapper (?)
jian actually has potential to become a lead vocal if cube didn't push her to become a rapper. idk why people rank her below sangah, imo she's lightsum 5th best vocalist after the vocal line. i love sangah but jian is so underrated. also idk why the rap duo isn't given either main or lead position, if cube put her as a lead rapper then people would stop shitting on her for being a 'filler'.
current positions : sub vocal
changed positions : + visual
lightsum has something that gidle doesn't, which are japanese members. gidle has diverse members from taiwan, china and thailand but didn't have a japanese member, which is important because japan is a very promising market for international breakthrough. having hina would let lightsum enter the japanese market with more solid approach. japanese people would support lightsum because of hina, and hina's personality is also veeeeery likeable. people are already comparing her with sana.
also, hina is pretty much their top 3 visual. adding her to the visual line would enhance her positions because she's currently lacking in dance, vocal or rap. hina has many important roles in the group, such as stan attractor, visual member and market breakthrough. debuting her is a smart approach because lightsum would be an all-korean group without her. international breakthorugh would be slower without her.
finally, lightsum's ideal positions:
chowon → main vocal, rapper
nayoung → main vocal, lead dancer, fotg, visual
juhyeon → leader, lead vocal, main dancer
sangah → main dancer, main rapper, visual
huiyeon → sub vocal, lead dancer
yujeong → lead vocal
jian → sub vocal, lead rapper, maknae
hina → sub vocal, visual
there, i fixed lightsum's previous shitty position with a new one that includes every members fairly according to their respective talent, instead of putting literally half of their members as a sub vocalist and calling it a day 
cube need to hire me fr
