Once you leave South Africa you're in for a richer, more frustrating, and more expensive experience that you usually won't regret. The reason so many fewer species are available further afield is the hunting is not the heavy commercial business it is in South Africa, a lot less intensive farming of species, a lot less game to chase, and a hell of an experience. Patrick also very correctly pointed out the poaching, which is often completely out of control. I felt like a a surprising amount of my time in Zim was the PH locating and pulling snares.
I'd branch out especially as your wife doesn't come, and see the wild side so to speak as it will disappear long before South African type hunts. Old Africa is going extinct and you're on the cusp of the last era to be able to experience it. It will change the flavour from vacation to adventure, and depends if that's something you enjoy and seek. For some like JHC-II (he was my boss not that long ago), who've seen too much of the wild side of Africa South Africa is exactly the desired flavour- and there's certainly no flies on it. Just totally different places and experiences, Zim can be as different from South Africa as Alaska is from Texas. Either way, you're lucky and enjoying the good life!