The surrounding terrain is also a factor that needs to be considered.
I used to operate from a 1.5km strip with a 1.25% gradient. I very, very rarely took off up the hill for two reasons.
Taking off down the hill the ground continued to fall away, and once a couple of trees on the end of the runway fell over one day if you could clear the fence you had another 5km before you had to climb. At the other end of the runway, the gradient was around 5% for about 1km, and then got a lot steeper very quickly - there was a 1300 AGL ridge about 5km from the end of the runway.
Also, I used the experience severe downdrafts near the hills. I once calculated that if there was 15 knots of breeze blowing down the runway at the upwind end there was an AVERAGE sink rate of around 300fpm between the upwind end of the runway and the ridge.
Whilst ATC determine the preferred runway at controlled airport, if a PIC operationally requires a particular runway in Australia they will usually approve it without a loss of priority (providing you notify them early enough).