Even if we compare their base combos...

GNB has Keen Edge, Brutal Shell, Solid Barrel, Burst Strike or 150 + 240 + 320 + 380 = 1090
PLD has Fast Blade, Riot Blade, Royal Authority, Fast Blade or 200 + 280 + 380 + 200 = 1060

So even against a trash mob it's not much different. SE has always balanced the lower levels as much of the higher levels. That's part of the reason the PLD rework took some time. They have to consider the levels that most raiders don't even talk about, like level 50 and 60.