A common theory is that Adolin will revive his Shardblade, which is confirmed to have belonged to an Edgedancer. Adolin becoming an Edgedancer is thus a popular idea, and quite likely too, I think. I think Dustbringers feel more interesting than Edgedancers, so I would like to see Adolin as one, but I do think that an Edgedancer is more likely.
My personal Dustbringer candidate, which I really hope happens, is Amaram. He is a brave soldier, and you could also argue that bringing the Heralds back through a Desolation is a brave (if stupid) gamble. He is defenitely obedient, and follows his masters and his purpose no matter what he himself feels about it. Making Amaram a Dustbringer would also make the story interesting in several ways. It would challenge Dalinars and Kaladins views of who a Radiant is. Seeing them confront the fact that someone who betrayed them has been given powers and bonded a spren would be very nice. It would also give the story a lethal antagonist, a fanatic with powers given to him by the Almighty himself. I could also see this opening different possibilites for Amarams character, from becoming more of a fanatic to redeeming himself.
Eh... I admit prejudice against Amaram. I don't like him any better than Kaladin does. As we saw with Renarin and Ym, it is possible there is more than one fledgling radiant per order.
Szeth was confident enough to take up the honor blade. Shallan... I can agree about her honesty, in a sense. She is tells lies and truths in almost equal measure, which definitely attracted the Liespren/cryptic. You could even argue that lies are, in a way, creativity with words. I think Shallans biggest struggle is being honest with herself.