When on heaven are you going to balance this game?
A game should be challenging, yes, but never frustrating. Calls for a better balancing are coming from more and more players but you either don't know what you're doing or you simply don't care. Shame on you in any case.
I can make a fair list of cases, but today the surreality of this game reached a new, spectacular high. My 100k, well balanced arena team, all 60, with all artifacts to 16 and full masteries, has been nuked by a single crit from a 5 star, lvl 50 Athel... In a normal game, such a player would have barely scratched me, but not here, because in your mind artifacts play a much higher role than heroes' level. So it doesn't matter if one works his a** off for months to level his/her heroes, when some newbie comes and destroys you.
Does this make any sense to you? If yes, just sell your company to someone else and stay well away from gaming.
Don't play with people's frustration.