I’m ranking based on my experience as f2p so access to other heroes is more limited.
1 vivica: one of two holy healers I have and one of three five star healers. She’s outclassed by many others but I can always use more healers
2: Isarnia: I often vote for her when people present their rosters as she often can provide a better defense down option
3+ joon, Lianna, magni, sartana, marjana: fast snipers are great early in the game. Luckily my first two season one five stars were marjana and sartana and they were huge improvements in my line up
I got some of them very late, so never got attached to them — Vivica after using Gullinbursti feels like a step down, even if she does have a cleanse. Magni, Isarnia, and Richard I got way too late. They’re still there “somewhere on the list”, but finishing Milena and Bobo first… I suppose if I got a costume, I might alter my plans.
The ones I am constantly using are Marjana, Joon and Lianna. Sartana is good, but got displaced by Kage and Panther for me.