Hmm? haven't hunted Tanzania- too expensive, but would love to have hunted Hemmingway's "Green Hills"!! The others you listed, IMO, are all comparable in a general sense. Never had any trouble with any of the people really anywhere. Never felt unsafe anywhere- but I would avoid bar hopping Johannesburg!
Even under Mugabe, as an outsider, I didn't find Zimbabwe much different from most other Southern Africa countries. The locals in rural Mozambique were fine and pretty friendly once they knew my intentions. The same for Zambia- very friendly and fun to be around for the most part. Each country and region seems to have its unique character.
The San in Botswana have got to be some of the most culturally and ethnically unique in all of Southern Africa. In some ways they remind me of the Acoma Indians of the southwest US and maybe some of the Yupik Indians of AK- two groups I've spent a lot of time around. I would not discount Botswana as a destination!
While driving around Zimbabwe, I was somewhat saddened by all the beautiful farm and ranch architecture crumbling into the ground- a Mugabe deal I believe. Parts of Zimbabwe are beautiful! The old growth, riverine forests in Zambia are neat for lack of a better description. Same for Mozambique. Parts of Mozambique are really very rural and the variety of landscapes is striking. I had a couple of very heartening, local contact experiences in Mozambique and will forever hold them dear. I do pretty well with Spanish so thought I could muddle through Portuguese... not!
As an aside, I know there is a strong connection between the peoples of Malawi and Mozambique with many families fleeing into Malawi during the extended Mozambique civil war. Still some big I unrest fomenting in a few parts of Mozambique- but your outfitter/PH would be best source of info and perspective on that. If a reputable outfitter told me no issue in his area of Mozambique, I wouldn't hesitate for a second.
No matter where you go- some unique experiences are always waiting.
