The best part about modelling is the next one is always better than the one before. Lets put this in perspective - literally. The pics have magnified the model by say 4 times. So you are seing things much larger than would normally be seen. You need to remember this before criticising your own work.
It is a beaut little dio, especially for a first timer.
The purpose of a dio is to tell a story, so yes a figure or two could liven it a little. The rocky verges could be from somewhere in the Italian hills area, so even a couple of HO gauge goats or sheep stopped in front of the jeep could add a bit of life, if you are worried about figure painting - name the dio "GI Nature call" and everyone would get the impression the driver is off relieving himself ; it also has a double meaning with the animals.
I once did a dio of a jeep with a flat tyre. I had a goat standing on the back seat chewing off a piece of the seat while the Gi's were occupied changing the wheel.....got lots of laughs.
Thanks for posting the pics. Looking forward to seeing you post some more in the future.