Lets assume ODI's for now as it is probably easier to tell whether it a flat batting track or not (weather conditions, pitch detorioration do not affect ODI's as much as they do for tests).
Regarding Wanderers in tests, didn't SAF almost pull off a 450 chase in the 4th innings chase against india last year? At least in recent times, Wanderers has been pretty flat in tests and odi's.
The Wanderers is one of the most fascinating venue in SA if not the world.
Its not as flat as people make it out to be.
Like I stated when the is moisture on the surface the pitch becomes something else.
When you live a bit of grass the pitch maintains its pace through out with a bit of swing.
There is not a lot of swing (or exaggerated swing) due to altitude, but enough to cause some damage.
And yes conditions also play a factor in SA.
It is very hot during the day in Jo'burg even in the early parts of the morning, by midday all the moisture on the pitch gets sucked out.
This explain why they prefer a day game to a day,night (where its a lot cooler).
It is during the day games that we get these 400+ scores. Even then teams must negate the movement 1st before launching an assault. IIRC in the 438 game Australia were going at 5.5 initial (1st 10 overs) and then built from there. As the pitch gets dry because of the heat it gets a bit easy to bat on as compared to the afternoon.
Here are the numbers (since 2000):
During a day game on average you get
34 runs per wicket, whereas a day nighter is the most difficult in the country (well, sort of).
A day night game has an average of
26.72 per wicket. Not a "flat wicket" now is it?
SA plays major opponents in 5 cities Jo'burg, Cape Town, Durban, Pretoria and my home town Port Elizabeth be it test or ODI's. And ill provide data as such.
Day Game (runs per wicket)
Jo'burg 34.78 (16 matches)
PRetoria 29.35 (20 matches)
Cape Town 26.78 (6 matches)
Durban 28.61 (5 matches)
PE 28.61 (13 matches)
Day/Night
Jo'burg 26.72 (15 matches),
overall: 30.79 runs per wicket.
PRetoria 28.92 (14 matches),
overall: 29.17 runs per wicket
Cape Town 25.83 (19 matches),
overall: 26.05 runs per wicket
Durban 25.65 (23 matches),
overall: 26.21 runs per wicket
PE 27.28 (11 matches),
overall: 27.69 runs per wicket
Jo'burg has the highest runs per wicket in SA, and not surprisingly the highest strike rate by batsmen. Overall they score 81 runs per hundred balls, whilst other venues are around 77 runs per hundred balls.
In India however they take the word "grave yard" to the next level
In 11 in Jaipur you have 34.86.
In 13 in Bangalore you have 35.61
In Kolkata you have 32.30 in 12 matches.
Jamtha, Nagpur 37.36 in 7.
Gujarat, Ahmedabad 34.61 in 15.
This is all since 2000, and the scoring rate is 90+ runs per hundred balls.