Tech stops on 737s used to be a very regular occurence when they were used on longer routes and not just on 200s. The 300 was quite limited on some sectors when I flew them. Cyprus to the UK was a regular for tech stopping.
M V
Its not just the lenght of the runway but also the surrounding terrain. On some runways takeoff in one direction can be much more limiting than in the other. Malaga is one of these. If the wind dictates taking of heading NorthWest then the hills get in the way, so weight is limited to improve the climb performance.