I agree with you.
My 2008 is supposed to have a quieter cabin than the earlier models but i wish it were quieter.
I installed the quietest tires that Costco sells
tire rebalance / rotate every 6K or 7 K miles
Played with the tire pressures a lot. ( mine is a 2wd SE which weighs less than a fully loaded Armada and I never keep any junk or clutter in the car so I run lower pressures than recomended and I increase when needed, )
My next step will be to dynomat the doors and maybe the floor. I did the doors on my motorhome (as well as alignment, less tire pressure, balance, rotate and bilsteins) and it helped. (Mainly it made the stereo sound better hahaha)
2008 Armada SE