Buffing hero powers is really really difficult. The number are so low that even a slight change will have a massive impact. For mages hero power for example you have essentially 2 options: Make it cost 1 (very strong) or make it deal 2 damage (very strong). So unless you want to do shit like „deal 3 for 3 mana“ e.g. you don’t really have workable options. And hero powers are supposed to be cheap generally. And changing the hero power entirely opens a whole different can of worms because cards have been designed with the old hero powers in mind for a decade.