I was suspect about Di2 until I bought one, now I can't imagine going back to a mechanical groupset on my primary bike.
However if there are enough improvements in the 2020 frame so that it's considered "revolutionary" vs. "evolutionary", and you think you will be keeping that frame for a while, then that's about the only reason I'd sacrifice the Di2. I don't know the Specialized line so I can't tell you how improved the 2020 is (the website certainly makes it sound revolutionary, but that's their job).
You mentioned your LBS has it. Test ride both. Mimic your real-world riding style. It should become fairly obvious if the 2020 is a considerably better ride in terms of speed, comfort, etc. If so, go with the new frame and upgrade to Di2 later. If the ride quality is fairly close, I'd get the Di2 and pocket the extra cash.