For a pro level kit, they're already pretty low. My impression is that the Evolution kits will be out along with the standard Saturns, not replace them. I think they're supposed o be a higher trim level, so they'll be a bit more expensive. If they discontinue a finish, those drums could get marked down.
I have a feeling by the way they have been rolling things out at Mapex, that the next big iteration of the Saturn kit will be wither next year or the year after. The big 30th anniversary edition kit they just did, their first all maple in 7 or 8 years, I think they;ll bring that back out as a relaunched Orion line in a year or two. I think whichever year they DON'T do that, they'll upgrade the Saturn fully. At that point you may find some being blown out. But keep an eye on Sweetwater, or email one of the guys there. If you tell them you're looking for a deal, they'll let you know if/when they have something to offer.