A great unit with mediocre IVs?

I just summoned myself a 4 star cordelia from the CYL banner and she has Mediocre IVs (+HP -Res). Seeing as her res is really bad anyways, i guess i could almost consider her IV's as neutral since Hp doesn't affect much. My only other good blue units are a 4 star lukas, 2 star sharena (not levelled at all), 4 star nowi and 5 star effie. Is she still worth levelling up?