Not sure if you have done so or not, but you should take a test ride on the 2019 before making your final decision. I was probably 50/50 on trading my 16 until I took the test ride. For me there was just too big of a difference in performance and comfort not to trade.
Our riding is a little different than most. We put between 8,000 and 9,000 miles on a year and most of that is 2-up. The trike might get those miles in 10 to 15 different states every year though (trailer in between). The new nav system was very important to me. It is 100 times faster than the old 1980's crap on my 2016, plus if you stop for fuel and turn your engine off the routing will start back up again when you get back on the road.
Overall I have found the 2019 just a better performing and enjoyable bike to ride/drive.