My guess is that I'm in the majority - someone who bought a cab and expected it to have a door on each side.
The DIY cab on my previous tractor had two doors. The intent was to be able to exit if the tractor was on its left side in the creek. It was never used for that but it was handy to be able to reach in either side to operate the FEL, and occasionally communicate to someone to the right of the tractor.
I'm all in favor of right side doors on cabs, but I'm not sure I'd add one if I were building a cab. I'd probably focus on rear egress rather than side, particularly in this application. Access could be achieved via a window rather than an entire door. No biggie though, I just like my cabs factory. I've yet to see a homemade cab that looked anything other than crap, but just my opinion, to which I'm entitled.
I added the hardware to make my MX right side door accessible from the exterior and it was well worth the $300 or so. I regularly access the cab from the right side on both tractors, but do not get in/out using those doors, and there's a lot more room in both of them compared to the BX.