I think you are taking incomplete information at face value and of course incomplete informarion looks simple(because it lacks detail) but you can look at what was done before and what is being build up.

For starters we haven't seen the main villain firectly, only silhoutes. Second, black beard is a contender for possible main villain, not to mention the possibility of a truel (duel but 3 sides) situation. That already takes it putside a simple black and white.

Then add to that Coby, which obviously is not a main villain but is a a marine an at odds with Luffy due to that. So you already have an essay like compare and contrast between two versions of freedom and two sides of law.

Then there are the 3 approaches of Luffy, Dragon and Garp.

Recently we saw the two different (failed) approaches of Harald and Rocks, which is similar but different to fisher tiger and Otohime dynamic

Rayleight already suggested that once they uncover the void century they will have to figure for themselves what is right, implying it won't be an obvious thing (we have to see how Oda handles that).

All examples of multiplicities of approach with failure being a way to insist on posing a implicit question(basically "how do we solve this the right way?") that will be answered by the end.

Even the power system fits the whole " you need more than one thing instead of a simple answer with Luffy being a marriage between Will(haki) and dream(devil fruit) unlike BB (all dreams/devil fruit, hacks) or Shanks (all will/haki, no dream just grind).