A fair request. It was pragmatic that we implemented only up to three dimensions in PATN (for Windows) V1. The significance of achieving our 3d display environment probably blinded us from thinking further, at least at that time. There is however no logic in assuming that there could be only three factors controlling the variation in a dataset.
What do you do if stress is greater than 0.15? At the moment, probably reduce the noise or the complexity of the data in one of a number of ways. I would not publish an ordination result greater than 0.15 myself.
If there is user support to go to say 5d, my strategy would be to enable selection of any 3 of the 5 axes to be selected to display in the 3d plot. The PCC strategy follows easily enough. Listing and output of the coordinates represents no problem.
Over to others to discuss-