Quoted from CrazyLevi:Shadow is more mode-based while most of your points on Doctor Who will come from multiballs and your playfield multiplier.
I think Shadow has much more balanced scoring. You can play modes, you can play multi combos, you can play vengeance, you can play the battlefield, or you can play multi-ball for jackpots - none will dominate.
DW has that upper flipper loop shot that can be repeatedly abused for points, making it more one dimensional and unbalanced.