Perhaps the simplicity of it, especially when it started. No fancy graphics, none needed really. Simple, yet extremely effective. But CM4 has introduced graphics in the shape of the 2D match engine. But that's gone down a storm - it's a quality addition. But it goes against the idea of simplicity as seen in the original CMs. Perhaps change is more than healthy?
But where does CM go from here? A 3-D match engine in the future? Little pictures of the actual players, instead of circles with numbers in on the 2D visual engine? What do you see as the future of CM?