It does have some limitations. Its similar to how the guy set up his Big Red in the 80's, except his didn't slide out.
Short of having to go up steps all the time, I like getting into the box for things. Everything is right there to mix, and grab etc, without having to run around the truck, but nothing saying they couldn't make a few tweaks.
The side opening doors work great 80% of the time. There are many jobs I've been on where side access becomes really limited because of where the parking is. Having one access at the back where the TM is located keeps things really simple.
I wonder if they've been looking at the Aussie setups for ideas?