I don't hate her. I like her but... she is just useless (at least on Nutaku). She is slow. Ok, it's not a bad thing at all. But her skill is just a shame. She harldy deals 6,5k damage on hit-weak pests. I just take my Japanese Iris from my skill activation team and she does 11-12k damage on pierce-weak pests. Pair her with Christmas Rose and they just nuke every ultimate event map bosses in one turn with their skills.
I really like this cute Cosmos but she just can't do her job. She is just a wall that does almost nothing. Even in a counter team she can't work well since her skill boost defense of only two allies.
Hoefully her bloomed form seems more powerful and get a nice atk boost.