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I have not been in Namibia, so I don't know what the lens requirements really are. However, I have both the 14-24 and the 24-70 and they are both excellent lenses. However, I rarely use the 14-24. It is very useful indoors when you have a small area and a wide scene. But I would think in Namibia you will be spending a lot of time outdoors.
The 14-24 would be useful in taking landscape shots, but on a trip the lens is bulky and inconvenient to carry. It takes up a lot of space on your bag and the large front element is kind of scary, being so vulnerable. As a result, most of my (local) landscapes for which 24mm is not wide enough are taken with the 24, portrait orientation, 3-6 shots panning, and stitched together in post.
Stitching is not hard. There is software that does it well. I use PhotoShop CS5 and it works, although there are several setup options that I sometimes have to try out. To be really certain of a good result, 30% or more overlap on the shots is recommended. I always do it handheld and 95% of the time it works. There are a few tries that for some reason PhotoShop doesn't seem to match up and stitching attempts result in two separate regions. I suspect in those cases more overlap would have helped, although I never know because the processing is long after I've taken the shot and I can't repeat it. For that reason I recommend you try each panorama twice. Digital pictures are free.
You can get special mounts for your camera that help keep the lens in the right position to get a good multi-shot panorama, but that plus a tripod is bulkier and less convenient than a 14-24.
If it were me going on a trip that might include both landscapes and wild animal encounters, I would take the 24-70 and the 70-200 and maybe a teleconverter.