I'm 6'1" and have had no problems fitting in the WK. I did notice that I have a little more head room in our Envoy though.
The doorhandle/armrest on the 08 is leather, and looks like it is stuffed with some sort of cushioning. I'd imagine a retrofit on our doors won't be a problem.
2007 GMC Envoy Denali - Summit White 5.3L V8 2WD
2007 Chevrolet TrailBlazer SS - Summit White 6.0L V8 2WD