I agree with you. And you got some really nice photos.
The 28-135 is my 40D's default lens. I just did a trip out to the Western US. Since we drove I could take my full complement of photo gear - TS, wide angle, tele, lenses, tripods, panorama stuff. And I made sure to keep them on the back seat for easy access.
Except for Aches NP, Moab UT, where I did use my Sigma 17-35 zoom for the wide angle views, the other lenses and gear didn't get used very much.
This was also a family tourist trip, not a photography focused trip. So I was shooting more like a photojournalist, or the old Leica with a 35mm lens prefocused method, capturing the images with what I had. Karate vs. Tai Chi photography.
Doing a National Park Service Artist in Residence program would be a lot different -
Site Name - Page Title
I plan to get a 7D and for that I feel that I need the 24-105 to get the best quality from the higher resolution sensor.