I have a Longhorn without the four corner air suspension. The appeal of the Longhorn trim is the interior appointments, leather, and woodgrain with a lighter color than charcoal or black.
As far as the 4 corner suspension, I have concluded that colder climates under certain conditions result in less than stellar reliability due to water ingestion. For what it's worth, I think you have a great vehicle which you can be proud of, and there's no detriment to your truck for not having the 4 corner air suspension option. The Longhorn trim is not as plentiful as other trims, this is something special. I spent months looking abroad before finding what I was looking for.
One option that is on my Longhorn that I would not do without ever again is the powered side steps; I also like the level 2 convenience package that includes the adaptive cruise, front and rear collision avoidance, adaptive high beams, and lane departure.
Enjoy your truck!