I don't think PA demonstrated that it's a bad idea. I think PA did quite a lot of things wrong so it is hard to draw a conclusion. Besides the issues with the underlying game, they barely tackled issues related to spherical maps, such as the difficulty in visualising them.
Populous the beginning, while not set on a sphere, does this sort of idea quite well.
The engine does not support spherical maps, but that won't stop anyone trying to add them. I think the first step would be to aim lower and start by implementing a flat torus (ie a pacman world). If you generalise the required parts of the engine properly, such as by writing more generic distance functions and pathfinders, then it will be easier to work on spheres.