I cant see upgrade sprues i can see full plastic units like Blood angels as they are cheaper to make ,the chaos marine sprues already have five sprues so an upgrade would mean five or possibly six where as a new sprue would mean two or four sprues like the death company or wolf pack respectively
So how many new plastic kits do you think we'll see?
The numbers stack up pretty fast but I guess it's possible, personally I think we'll see something like the space wolves kit where you get a buttload of bits to make your models with.
I dont really think it's feasible for them to have 4 boxes for most new units, heck it'd be 5 boxes for different Bike units, 4 boxes for the riders if those a true. We'd be looking at 20+ new boxes and I dont think they'd do that.