I have never understood the more maps is better. I find that usually people prefer 1-3 maps and would rather play those than other maps.
Well, in W:ET you had some good standard maps, like oasis fueldump, goldrush. But a lot of custom maps were popular or semi popular as well. There were like 20 good maps that got played a LOT. Thinking about Supply, Venice, Caen, Marrakech streets, ...