I would say that since Malosi hasn’t been released yet, level joon up to 3/70 or any variation and try get a sense of what you like and don’t like about his speed, damage, and how useful that blind can be to your team.
I would suggest that Malosi shutting out all status effects is more useful than a blind for a support hero, but he is nowhere near the damage dealer of Joon.
I would also keep in mind Joon has a costume and depending on whether you spend or try to pull costumes may influence this decision as well. I would argue Costume Joon over Malosi every day for raid defense, but Malosi’s special has a uniqueness that will be immensely helpful in war strategies, and challenge events. Imagine enemy bosses never getting off there annoying status affects (whoop! whoop!)
Try and play with Joon a little, it’s what I’m doing with Freya at 3/50 it will honestly help you decide what your team needs