First off the air ride issue is not just an issue with the Rebels, its all models of RAM's with air ride, its just more pronounced with the Rebels because the '16-'18 models only come with air ride. As you pointed out its in sub-zero conditions where it occurs the most, but there has been a few cases where there was general failures. I live in the Seattle area, I have experienced zero issues, and I know 4 other people in this area that have Rebels or Laramie's that have air ride and they have had zero issues with it. The other thing to remember is public forums like this your going to see more of the bad than you are of the good, human nature is to bitch about whats broken not compliment on what is working well.
With that said the Rebel looks are awesome, and the Hemi packaged versions are top notch. If you want to have the looks of the '16-'18 Rebels but not have to worry if your going to have air ride issues then wait until the '19 RAM Warlock comes out, its a '16-'18 Rebel packaged as a Warlock and has coil suspension instead of air ride. But if you are really wanting one of the older models I would strongly suggest to get a '18 main reason because of the 8.4 UConnect which has Apple Car Play/Android Auto support, that was the main deciding factor when I bought mine, I use Apple Car play daily and it blows away the factory NAV hands down, its even inspired me to change out the UConnect in my '14 Challenger to a Kenwood system that has Apple Car Play.
Good luck on your choice.