I don't necessarily expect a 3rd. Wouldn't it depend on whether 2nd is a success first?
Where would 2nd and 3rd even end? I imagine maybe end of Alabasta for 2nd unless the want to rush the show a lot more?
Season 3 Skypea? Really makes you wonder how compressed will the story be if this goes on.
It's a good thing for Wano at least.
Alabasta is where the story really starts to shine so it means that people will want more. I'd say
Furthermore, Alabasta will be much closer to the original material as there will be no real need to bring the bad villain toward the middle of the second act, the story naturally follow a classic storytelling pattern from wiskey to the end with Robin.
By episode id say:
1 (1h-1h30) : Logue Town + Cape Laboon + Wiskey Peak (festa)
2 End of wiskey peak(battle) + little garden + bad guys misselinious
3 Drum
4 End of Drum(with Ace) + Bad guys misselenious + start of Alabasta + rebels
5 Yuba + Rainbase, ending with the win of Crocodile on Luffy
6 Rebels + Vivi's flashback + Start of the war
7 Battles ending on Luffy Arriving
8 Defeat of Crocodile + Palace + Ending + Ending on Robin.
Alabasta is very practical in term of narration. We can create something close to the material while still keeping the rythm of a normal serie. Skypiea on the other hand is another challenge.