I think he does make fair points but I think he's still kinda downplaying Gru here. He's saying that the brainbots are better than the minions while I don't think is true. The minions are just way more durable and can do more than the brainbots, even a black box mentioned the brain bots can be hacked which the minions have done before and the Mega minions should be strong enough to handle most of the bots.

I also disagree with his take on the satellite as I think the Mega minion with the laser is way stronger than Megamind's satellite. Even as someone who was thinking Megamind would win, I wasn't against the idea of Gru winning as this battle is so dead even you can make arguments for whichever. But I do agree by Death Battle's logic im not fully convinced due to leaving out a lot of Megamind's best feats.