Poison counters are fair game, but many players feel they are unfair
He comes in indestructible and his ability automatically triggers at end step, so this feels sort of like an Etali where you pay one mana more to guarantee at least one trigger while also draining your opponents for a bunch of life
Great for you if youre able to take advantage of them, but if your opponents like playing creatures like Niv-Mizzet (Parun, Reborn, or the Firemind), youre going to want a board wipe that can actually take these problematic cards off the battlefield instead
Because it's a Hate Bear leader or adjunct, or a Voltron, Aura, or Equipment leader that cannot be countered or answered instantly
Cerberus is that while its obvious how much value you could get by tripling up some ridiculous spell, the floor on it is abysmally low
In Legacy, there are even more three drop options like Uro, Titan of Natures Wrath that are capable of taking over a game on their own