.... unless you're like me and can't abide the GX's side-hinged--and the wrong side for North America, no less--rear door. ....
The right hinged full door never bothered me on either of my Land Rover Discoveries even though it is on the "wrong" side like you said.
While I love having a split tail gate on my LR3, kind of like a Land Cruiser except mine is shaped funny, there are pros and cons between "swing door" vs "flip up hatch".
The obvious nice aspect of the hatch top section is the instant rain coverage. Really, that's it I guess. Splitting it to create a short tail gate is an added bonus but then you start to loose rain coverage and create a distance to cargo space issue when reaching in. Yet, we all still kind of dig this design don't we.
Considering a full door swing design though presents other pros and cons:
Pro: when open, you can build a fold down work table/ cooking surface right there on the door. Super convenient in some ways, just swing open, drop tray, get to it with your cook kit on the left in the cargo area and easy to reach because you're not stretching over a little tail gate. But you are leaning on/over a potentially very dirty rear bumper. When clean, or with something rolled over it, that little bumper is almost like a tailgate. At least on my 2004 Discovery it is due to it's depth and flatness.
Other pro- if you like to have either a roof tent or rack mounted rear awning, the side swing door works better, particularly in a layout with the root tent flipped open over the rear. The tent floor then becomes a roof over the rear area for cooking or other uses if you have a lower annex connected.
Another plus for the swing door is it being a tire carrier already where a tire belongs. On the LR3, or Land Cruiser, you have to leave a smaller one underneath or invest in a bumper swing arm carrier which ads one more step/action to access the cargo area.
To me the worst thing about the swing door though was in rain and snow. There's just no quick way to utilize the cargo area without letting in rain, especially snow drifting around, even in just a couple minutes so if you have a sleep area set up there, your bed basically gets wet if you haven't prepped for the weather.
To build back in some of the benefits of the swing door but onto my R3 with the split hatch design, I did install a Kaymar rear bumper with dual swing arm carriers and customized the tire carrier arm to also accommodate a 2" receiver specifically, and only of course, a bike rack. This actually works fantastically because the bikes are roughly 48" off the ground when off road and are higher than the departure angle line off the underside of the rear bumper, such that you'd have to really get into a gully or drop ledge to risk dragging the rack itself, above which are the actual bikes. This also removes all issues associated with bike racks in towing receivers which always get in the way of using the rear area.
I suppose, overall, I really prefer the split tailgate but would choose a full lift hatch next, with swing door last now that I've lived with all of these designs over the years in different settings. The only full hatch design I've had has been on my BMW wagon but I have camped out of it a lot as well and do find the larger instant rain cover to be nice in that specific situation. In the BMW though, with less rear cargo area after the full size spare takes it's own space, I place the ARB fridge behind the driver seat and access it through the side door leaving more room at the rear for the "kitchen bin" or mtb gear bag, etc.
For me, the GX would be way too small but I don't travel light. Just the cargo space alone is what drew me to the Land Rover Discovery 1 in the first place with nearly 48" floor to ceiling and 72" door to seat backs. Later I briefly had a LC 100 series and found it to be a very nice size overall as well after removing the rear seats. It was wider and longer but the Land Rover being taller inside worked better for my way of living.
The LC100 also just seems so easy in terms of aftermarket. Plenty of choices and kind of unlimited too. Maybe you wouldn't get the 2nd fuel tank, but it's cool that you could choose from a huge fuel tank, or just a small one above the spare, or a water tank too. I like those long term options without having to go full custom for everything.