Good plug. I had been looking for a freeware phaser lost in my digital jungle. It had a decent phase but also a panning feature that brought out the feeling of depth.
Haven't run into the problem, but remember tech support from P&M replying to a feature request to add stereo to their stomps. The guy said that they were avoiding a mess of phase cancellations that would happen with conflicting stereo fields bouncing around in the mix, turning things to mud.