that could be due to the fact that the male aes sedai purposefully made the ways to be light and inviting, complete with trees and grass. think about it, the skimming void is limited in a way due to the fact that its a quick a-b journey and the ways are slower and more convaluted. they'd need to be bright and shiney and full of growing things.

the darkness only came to the ways due to the taint on saidin, which is what they are made of, building up over time. perhaps if the ways were made by saidar they'd still be full of light.