Yeah, basic theory says pad size makes no difference since F=PA and a bigger pad just means less force per unit area, but technically there are two points that do give more pistons some advantage: a) bigger pad area = better heat dissipation which I'm sure you knew (though maguras don't really benefit with their "4 pad" split nonsense, one big pad like M810/820 and E4/V4 does) , and b) the center of force application is further out on a 4-pot brake compared to a big 2-pot, so even for identical total slave area which would give identical hydraulic leverage, the 4-pot would actually have a small mechanical leverage advantage at the rotor.I guess more pistons makes sense to me, as all of that power is translated through the pad to the rotor
So you can still be correct for those two reasons.