It might be a problem of pressure Oda's exposed to, he wants to complete the whole universe, but it is so complicated, he has to rush to be even able to finish it at all...and might want to do sth else entirely, aa~h, raugh life to be a mangaka :(
Per the discussion on plot-based vs. character-based development, I truly think it will come back once the crew is strong enough to back up their world-changing dreams. They are outclassed in almost every category right now. They are fighting an uphill (up-mountain level) battle. It seems out of place to a certain extent like they aren't "taking the situation seriously enough". So I guess I understand Oda's perspective on not putting it in now. For me, I find it hard to imagine it doesn't come back once they can actually start to relax again.
Yeah, I didn't say Oda should put it in the story during this particular developement, but again, the more "villains" are made, the more difficult it is to get to the peacefull period of time, hopefully there will be something like that again and in the right time ofc :)
: Luffy~ XD