Yeah I think the reverie will be shorter, because non of the SH's (except Vivi if you count her) are there probably, so Oda can't go on too long with that. But the original comment I replied on said he would be back after Wano, and I think Wano has the potential to become a monster arc. Like the closing chapter in this two yonkou Saga.
I think a lot of royalty will be introduced from both name dropped places as well as new places that will show up later. A lot of kings already have experience with the SH's so I hope they're not afraid to support Luffy and maybe even make a fist against the WG. There will be no doubt an uproar or disturbance during the event, which forces the marines to spring into action. Hopefully showing us Greenbull.
Have no clue really, it can go a million ways. Interested if there will be a Wapol vs Vivi round 2.