So my own personal issues & feelings on Butcher…
Early game, he should be a MENACE.
Just like in original Diablo 1, when you hear that blood chilling, “AHHHHH…FRESH MEAT!” You should dump a load in your adult diapers, and go running for your Mommy/Healer/Tank/entire team. He’s a HUNGRY Butcher - he wants your MEAT! He’s like Hackin’ Pete from that other game franchise, and he’s gonna chop you all up!
But then, mid-late game, he IMHO, does get -way- too powerful. He as OP said, can just press E, and nearly insta-delete anyone. Not saying there is zero counterplay to him, however due to the nature of HotS itself, very few times will you be able to pick talents, etc to counter that (since no item buys, can’t just stack armor, etc.) So what do you do to counter him?
You can try and rely on your team, to always be with you, to focus him down, stun & CC him, etc etc. Though as any of us who have played games past the tutorial know, this isn’t really a viable strategy. I think at this point, it’s gonna come down to, does the majority of the HotS community think he’s OP, and needs a tone down, or are too many players simply lazy/uneducated, that they need to focus him early, to keep him from stacking meat? (I feel the latter may be the case.)
I know that when I play as him, I HATE early game. Butcher feels really squishy for a melee champ, and easily focused down. Perhaps give him a trade-off? Reduce the effect of the max stacks of meat (btw I HATE any mechanic that is “lost on death” and I usually avoid these champs/talents like a Plague Inc level plague…) and maybe give him some extra early game survivability or farm, to help offset the difficulty of getting the initial meat stacks.