CIELab is not perfect, but is probably Good Enough, especially for the kinds of use cases as described in this article. One of its main flaws is lack of hue constancy, particularly in blue.

There are any number of colorspaces that have been proposed that are better. Some are complex and ad hoc, such as two different releases of CIECAM. Others are relatively simple, such as Jzazbz. IPT also comes up a lot. I think the issue is that there isn't anything resembling consensus on which of these "more perceptually uniform" color spaces we should use. So a bunch of efforts, including freieFarbe, use Lab.