A couple of rather obvious points no one seems to have made:
How wide is a tailgate? ... Four feet tops. Why is it a pain to walk that distance from EITHER side?
There's no safety issue. You don't have to stand out in the traffic to open your tailgate, no matter which side the handle is on.
Putting the hinges on the right actually has an an advantage when you park on the side of a crowned road: gravity helps keep the gate open, so it won't slam on you if a gust of wind hits it. Left hinges would have the unfortunate opposite effect.
A gate-mounted spare is the easiest to access when you need it. You don't have to crawl in the mud and fight rust and grime, nor do you have to pull all your cargo out and lay it on the ground to access an under-the-floor spare. And of course, it saves cargo space.
For unloading, a liftgate can be a pain (Literally, if you're tall enough to bump your head on it, which I am.). It's the one thing I dislike most about my X-Trail. The worst is when you try to take an armload of stuff out of the back. If you have a swinging door tailgate, you just bump the door with your knee or butt, it closes and you're on your way. With a liftgate, you have to put the load down, reach up and slam the gate, and gather everything up again. It's a pain, and I curse the design every time I go to the supermarket or lumberyard.
If the X-Trail came with a swinging tailgate and outside spare, it would be damn near perfect as a mini SUV.