As others have said, android auto and car play came out in 2018. I can get Spotify to work on my 2017 through the usb and Bluetooth interface, but it’s Neanderthal compared with native car play.
I believe the car play /android auto issue is tied to the UConnect hardware. 2017’s are running UConnect 3 while the 2018’s are running UConnect 4. 4 is obviously better and more capable.
Regarding ESS, it became standard with January 2017 builds, so 2017 Pacificas built between March 2016 - December 2016 don’t have it.
Another thing about the 2017’s, they had a design defect that was identified with IIHS’s small overlap crash test, where the front door came off the car during the crash. Chrysler redesigned the door starting with the September 2016 builds. When IIHS retested, it was fine.
So if you’re looking at 2017’s the sweet spot are the September - December 2016 builds.
I’ve had a few 2018/2019 loaners along the way and honestly, besides car play, there’s no noticeable difference.
Regarding the transmission, they’re all the same, including a brand new 2021 limited AWD rental we put 1200 miles on while on vacation earlier this year. This transmission does not like to downshift. If you ever drive a BMW or Mercedes in sport mode, you’ll understand what I mean. It likes to stay under 2200 RPM and has been designed for max highway mileage.
Car for car, I’d go with a 2018 over a 2017 however, if you find an awesome 2017,
you should definitely consider it.