stuns arent broken (i.e. they aren't too weak or they aren't too strong) theyre fine as they are, the only people who really die to stuns are the people who push up close to the stunned player, then those same people go on to complain about a 'cosmetic stun'
imo you deserve to be punished for pushing close to someone whos stunned, otherwise it would be as good as a detain (detain = killjoy ult/gekko ult status effect)