My thought has always been that Adolin is either going to become a radiant, or not make it through the first half of SA(books 1-5). As I hope Adolin doesn't bite the dust, I think he's going to become a Dustbringer.
There are the obvious attributes of obedient and brave, which fit Adolin perfectly, but a lot of my reasoning comes from gut feelings about how I picture the Order of Dustbringers. Take a look at what we know about the combat oriented orders. The Windrunners do what is right, regardless of the law. The Skybreakers always follow the law, regardless of morality. The Edgedancers look out for those who have been forgotten. I see the Dustbringers as the order that does what is necessary, even if it is distasteful. This could tie in to how they seem to be misunderstood and have a bad rep, and matches up well to Adolin's encounter with a certain Highprince at the end of WoR.
I couldn't find it, but I remember a WoB that said we have met a radiant or proto-radiant from each order by the end of book 2. Who else other than Adolin is a good candidate for Dustbringer? Also giving one of Roshars top duelists an uber destructive skill set like the Dustbringers possess, is imo too good of an opportunity to pass up