Apple almost never pre-announces products, so we don't really know, but they've strongly hinted the new keyboard is coming to at least the 13" MBP in the next revision. I don't remember the exact phrasing, but it was a comment from VP Phil Schiller something like "it's important for all our 'Pro' products." (I remember it was something that made it unclear whether the keyboard will come to the Air, although I certainly hope it will.)
I did see the comment from someone saying it'll be upgraded to a 14" the way the 15" became a 16"; while that's a reasonable guess, I don't think there are any supply chain rumors supporting that yet, and the 16" update had rumors nearly a year in advance of its release. My personal expectation is that we'll see an upgrade to the new keyboard in the 13" before WWDC, but it'll stay 13".
I'm still holding out on my 2015 MBP as well, hoping to get the new 13" with the good keyboard.
Otherwise... surface book it is...