I'd like them to work on more new stuff rather than continue taking from GameJam personally.
Not everything in Dawnguard is Gamejam - Armoured Trolls, Gargoyles, Soul Cairn+everything within, Crossbows (iirc only spears were in Gamejam) etc.
Personally, I want to see a bit of both - the Gamejam stuff and entirely new stuff. After all, if they put no more Gamejam in we'll never get spears D:
...not that we're likely to as fitting them into the existing game could be awkward with perks and such...