True, they are coming out with the RST package, but I was under the impression that the other Chevrolet Tahoe and suburban trims will remain basically unchanged.....in terms of engine and tranny. Pleas correct me if I am wrong.
My understanding from the press release and the articles I read was that the RST appearance package will be available on the Tahoe and Suburban in both LT and Premier trims. The RST performance package with the 6.2L engine and mag ride, etc. is also supposed to then be available on the Tahoe in LT and Premier trims as well. The suburban will not get the larger engine.
For those reasons, I would say the Chevy lineup has the greatest change in offerings from 2017 to 2018 model years, granted it isn't an overhaul of the entire platform at all trim levels and all models. Like I said though, still a lot more changes than what has been announced for the other two GM brands so far.