Being weird is an automatic handicap. The current layout provides a wealth of data in a grid, something that can be represented in the simplest of data structures. If you're going to switch to circular and have strange shapes and free-floating elements, you need to make up for all the complexity you've added by showing significantly more correlation. This does not in the least. If you want to see alternative layouts that really give the current a run for its money, check out Stowe's.

Ptable.com has had this one for a decade. What gives?

An a priori argument against the accepted knowledge with evidence supporting the opposite conclusion: http://essays.dayah.com/spam-unsubscribe-not-harmful