Fighting experience
Hi, am new here and know little but my suggestion is to reward with level experience the heros used in quest and arena battles, it will be a huge help to new players so we can save Iso-8 for our best units or the ones we want to promote faster. It's very depressing to fight against maxed out units with our rank 1 lvl 1 hero once you pass 10 win streak. Getting experiencie from battles could greatly help to grow our low tier characters and let us focus on our best ones.