I think he might get his first "major" fight against Kuzan, when the BBPs fight against the Strawhats. Sabo still has to deliver Cobra's message afterall. He could be the 11th Mugiwara that's still missing for that task.
With such a big DF advantage Sabo might make it an interesting fight and Oda can awaken his fruit there aswell, if he wants to.
Awakened logia vs awakened logia then and Garp's vs Dragon's fighting style. Would be cool I think.
Logia awakening is going to drop then anyway, thanks to BB's Yami.
And for his final fight I can see him fighting a Gorosei member. I have a gut feeling that the Gorosei either get taken care of by Zoro, Sanji, Sabo, Law and Kid or purely by non Strawhats- Dragon, Sabo, Law and Kid (+1).