You need a snorkel because that helps to keep the dust out of your airfilter and is useful when crossing water. Main benefit is for the dust though.
You may need (or hopefully will never need) a bull bar in Africa (and other countries where there are stupid goats/sheep/cows around). Hitting animals is a real possibility and a bullbar should limit damage to your vehicle.
If you don't use a 4wd, then a winch might be more usefull than if you had a 4wd. Chances are that you might get stuck easier, but then you should be able to get out of most situations without a winch. You'll be surprised what you can do with a 4wd with the right technique.
Low range gears are generally a good thing.
We travelled alone from Oz to Cape Town and went to pretty remote places. We decided to get a winch (never used it) and a highlift jack (never used it) and lots of other recovery gear, which we did use, but to help other people. Most of it comes down to technique and a bit of common sense.
Ground clearance is good, but not essential. It will limit you a bit to where you can/want to go, for example, we went to some lakes to the west of Olgii in Mongolia. There were lots of big round rocks on one of the roads which wouldn't have been possible in a 4wd campervan without potentially breaking something. We even had a few moments with good clearance.
Personally, I think that you don't really need good ground clearance in sand for example, you need good traction. Ground clearance becomes more of an issue when it gets a bit more technical.
I'm sure there will be someone else to contradict my thoughts though...