This is my opinion about some 5* heroes, give me your opinion (i may be wrong, they are notpopular so i don’t play a lot against them)
I will start with Khagan, good stats, good power, just a bad mana speed. What about changing his mana speed to average ?
Elena: She has a riposte power, but when she does her ability (if she is not dead), she has very low hp, she is about to die, and without a good healer (can have only vivica for free), her power is a waste.
What about buffing her defense ? (New! All Updated Hero Rosters , she has only 2699 stats, she can gains 50 defense easily, or low a lil her attack and max a lot her defense)
Quintus, maybe change his ability, more damage or a buff for nearby allies (something like merlin but for allies, when nearby allies are full mana, they emit an electrical charge that deals 100% damage, or something like that)
Leonidas. what about, deals minor damages to nearby ennemies ? but low the mana to target only.
Elkanen: Maybe a defense bonus to his ability, like gets +34% defense,or a defense buff against special skill so he will be playable as a tank.
Kadilen: Allies gain lifesteal (10%), increase by 5% when allies get hits (up to 50%)
Thorne: i like your idea where he takes damage for allies.
Richard: hard one, don’t know wha he can do more, maybe a green shield for him.
Some other heroes need changes, but here are the priorities in my opinion.