Ruub was good in NecroMoga, when necromoga was a thing...a lot of cheap champ out and a lot of deaths to proc his signature abilities
Klzik Grimlic are great Idk if I should call them heroes but: Malandur doesn't feel like a leader. Korona is great Salaam, idk yet. Just got him. Firemaw works well on a complete fire eater/ fire acolyte bg No goblin, imp "heroes" yet
Yeah, Mena is fine. Bliss has some boring upgrades but is pretty legit (a few more HP would be lovely). War caller Fiorn is probably the one that could use some love. He isn't terrible but doesn't really shine either.
Mena is more than playable in mag amp and elves. grimthir in illusions is great. fiorn and dugon are playable but could get some love. anaru is a nice tool for rangers now. i personally run bliss in kf adaptive and she is not a must deploy, but if you get her is a real power up. outside of the adaptive spellspam context, i don't see a lot ofspace for her.
It seems like pretty well every hero has diverse upgrade paths except for dirge, who has 3 ranks of evasive on his second upgrade line. Some other options would be nice, seeing as every other hero (or at least 95%) has 3 different options on both paths