If this rumoured laptop has a bigger screen and a new keyboard as people say, then Apple would most likely want to make a loud drop with an event.
depends since the screen change is largely if not completely due to a reduction of bezel thats not a huge story on its own, so then it comes to the keyboard.
if the "new" keyboard is actually the v3/v4 butterfly that still retains crappy travel, lack of esc, lack of inverted T homing arrows, touchbar etc.
most people wont care because just like the last few revisions of butterfly its not a user facing change its just aiming to improve reliability for the sake of apple's warranty claims/bottom line
whereas the hypothetical 2020 redesign they could be more radical by making the keyboard like the old retina's with minor changes like maybe a touchbar above the function keys but still having them, touch ID in the power button etc.
truely take the best of both worlds.
now one could argue the 16" could have radical changes like my wish list above but then the 16" would be the od man out in the current lineup.
not to mention if they make a big deal about MBP this year the likelihood of another big deal about MBP next year is less likely.
thus i think my OG silent drop is not only the most likely but the preferred option.