Sorry Drip but i think most players like to compare the numbers from Helper squads which means unfortunately high HP units will win out, I'm looking at your Peach. Also many just go for eye candy as well (rainbows bleh).

Some people have partys which use Dendro and Cymbi which is a really strong hit duo, capable of one shotting most mobs. Add on more aoe like BB or Cattelya, if you dont have those add units like edelweiss (2 unit aoe and heal). Personally 4 aoe rainbows + Cymbi is better than 5 rainbows.