A few smaller black ones are fine, but a pie with fairly white crust, but with lots of large black spots, that's undesirable to me.
I find the best ones to have an even browning without any larger spots. Scattered smaller spots are fine, but there's nothing attractive about too many charred spots.
Those wanting large spots has never said they did it for the taste, and that's where I don't understand anymore. Unless you make pies just to look at.