Even though one may say mAyA is illusory, it has its effect which manifests in the individual soul or jiva and this "effect" is not illusory, it is for real. Hence, even an illusory mAyA has to have its origin and a specific locus. It may look very wiseacre to make remarls like "Since maya itself is illusory, the question of locus does not arise.", etc., but even illusions have to have a cause or origin just like we say optical illusions and ascribe those kinds of illusions to the imperfections of our human sight system. mAyA, if, independent of both brahman and everything else, becomes another reality in its own right and hence Brahman is no longer the only absolute Truth; mAyA and brahman thus become, two absolute Truths, thus again showing off the flaws in advaita.
It was this "locus of mAyA" business which, I think, gave rise to different schools of interpretation (such a bhAmati,vivarana etc., up to the Sachidanandendra Saraswati school), differences and arguments within advaita itself. Kindly brush up these aspects also. IMO, Sankara failed in giving a clear idea of whatever he meant, even to his four immediate followers and, as a result thereof, even these immediate followers went on to justify and explain away their guru's teachings, each his own way. This exposes the deficiency of Sankara's exposition of whatever his ideas were, as also flaws in whatever he expressed as a lofty philosophy.
