Sorry but I am not the kind of guy who just assumes Oda is a bad writer... So I will not jump to the nonsense conclusion
Oda is a fool but not that much.
Oden alive would destroy everything he built/write this arc.
Keep the same energy for the next couple of chapter guys when it's truly proven that it's truly Oden, and Oda is coming up with some explaination of his own be it time DF shit or something...
I'm not saying Oda is stupid, and I simply do not call this move stupid, I was advocating that he will show up at one point actually, and my reasons for that is, I simply can see Oda doing something like that, and that's because Oda tried to be VERY restrictive on what to show from Oden... VERY VERY VERY restrictive, where even his clash with Kaido was two pages LOL... the long awaited fight was off-screened... everything about Oden was off-screened... you only do that to him and Kaido's hybrid form when you want to show them LATER more.... and showcase them in FULL capacity... as a writer, this may sound dumb for you, but Oda literally is the type of characeter who would showcase every single detail about SIDE characters like freaking Baby 5 or Senor Pink for god's sake... again, the arguments may sound not good for your taste, but that's what oda does... when he keeps something away and not show it, it means it will be highlighted later... as simple as that