Shotgun only does really good damage if you're right in front of the squid when it uses it. If you're a few blocks away, it will not effect you very much. Seriously, most things in the game have projectiles that have a greater range than shotgun. Even creeper. I honestly think that using witch against squid is better than using horse, since witch has a bit of a longer range and a shorter cooldown for daze potion, so the squid will be less likely to avoid getting hit every time. But when you use horse, the squid will probably just SS through bone rush and bone kick, which renders it as ineffective. However, if the squid fails to do so, it will most likely get shredded or tossed off the map. Another thing with horse that ties back to what I mentioned earlier is that horse is extremely close range, so you will also take greater damage from shotgun when you move in close to attack. With witch, you can kind of just keep your distance so that shotgun will be less effective, but you can still keep jumping back and forth with daze potion. As for cow, I do understand that it deals a lot of damage, and I do think it may need a nerf in that area. However, cow's attacks aren't that hard to dodge. Milk spiral moves slowly, so you will most likely have enough time to move to the side before it hits you. And you can just triple jump over angry herd. As for stampede, it gets reset every time you are able to hit the cow. So you spamming daze potion at a cow will probably mess it up if you are consistent with aiming.