I'm guessing it'll be less about what misadventures they get into but rather what amount of screen time they'll get. Things are going to probably feel samey, but they'll probably act as a fan service cushion to the over-arching story they want to make.

Well Abrams has said several times he wants to recapture the feel of the original trilogy. If you remember, George Lucas designed the original movies to be essentially told from the perspective of the droids (like the film The Hidden Fortress, that was a big influence on GL for Star Wars).

Besides which it makes much more sense for both of them to be there in this trilogy than they were in the prequels.

He's going for a 100% safe, forgettable, explosion-filled crowd-pleaser, just like his Star Trek movies. Of course he's going to cram in the droids just like Lucas.