Kinda agree on this one. There are certainly some 5* that are useful even at 2/60 (Telluria being one shining example), and at 3/70 you’ve unlocked 83% of their potential anyway.
Telluria at 2/60 has the following stats:
430 atk/ 583 def/ 999 HP
Except for her atk, she actually has better stats than Caedmon at 3/60, widely considered a very balanced 4* green. But if you’re using Telluria as a hitter you’re doing it wrong anyway, plus her special more than makes up for the lackluster atk. I use her in my Caedmon+6 and Peters 3/60 green stack to great effect, and do not regret one bit the resources spent on getting her to 2/60.
(plus Telly being one of only three green paladins in the entire game really helps with the class quests as well)
Mist kicks ___ in boss battles where enemies like to buff themselves (such as Guin in events). She can turn almost everyone in sniper. Too bad you don’t have Jackal, those two together are nightmare. Brynhild is awesome too, especially if you miss green (like almost everyone in war runs blue tank, so one needs quite a few greens). Valkyrie brigade.