I’d pony up for the extra roster space. If you can do a 30 pull, you probably can pay the gems for the extra space. If you must get rid of heroes:
Any season 1 3/4 star without a costume. Otherwise:
Danza, Triton, Agwe, Boomer, Vollermmork, Mack, Ahhotep (others may like him more than me), Gato, Gobbler, An-Windr, By-Ulf
oh sorry, I wasn’t clear. I wouldn’t necessarily feed away some heroes that you have fully leveled. If you’re really struggling on space you’ll have to decide on whether heroes you don’t use are worth keeping or do you pay for roster space?
Mack would be an upgrade to Cyprian/Boril
Ahhotep is definitely the best purple hitter in this roster, so max him first
Gobbler is the only anti-minion hero in this roster
otherwise I fully agree with this list as well as the rest of the advice.
level up your 3 star costumes! You already have the heroes maxed, make them better by maxing their costumes.