A poly based off the Pro 3 would smoke a Poly Evolver in every way imaginable, aside from early aughts nostalgia, which I def do not share in, for those were dark times. It'd have better oscillators (both analog and digital), better filter (or even plural), better UI, better sequencer, etc. I'm sure SS will argue with this, but I'm not hearing it.
I'm not sure we can entirely rule this out by Dave's comments. He did say analog, but he didn't say purely analog, even though that's what the question was getting at. Although he perhaps wasn't strictly talking about the next two synths, he did say, "if something has a VCO and filter", which a poly based off the Pro 3 would still fall under. It just happens to have digital oscillators as well.