Yes you can argue that Shaq at his peak was a greater scorer than Kobe. Kobe can shoot but Shaq has unmatched strength and quickness+athleticism for a big man. There's no way to measure which is more important: Kobe's footwork+ jumper or Shaq's unmatched strength and athleticism. So there's no way to argue either one, it's completely subjective.

Field goal percentage is an oversimplifcation, that's why there are stats such as points per possession and true shooting % that take into account 3 pointers being more valuable than a 2 pointer. Basically, they are like the more accurate version of field goal percentage. And guess what? In Shaq and KD's best seasons, KD has a better true shooting % than Shaq.

Shaq's true shooting% hovers around 57% to 60% in his best seasons, KD only has 3 seasons under 60%, the rest are around 63% to 64%. So even if you use your logic to argue, KD is still more efficient. So no, a wing such as KD that scores in volume and is super efficient can still be in the discussion.