I have asked for the pan feature, as well. Some synths have it, like Hybrid, Sylenth and Serum (of course O2) and some don't such as Massive, Halion 6 and others. I find that the synths that get more time in my set ups are ones that can be panned at the OSC (manually, not unison spread). However, it may be a quantum leap to split each mono engine in Pigments into 2 stereo signal paths. The new Bolt by Nektar is pannable, as well, at the "engine","OSC" or "wave" level respectively. For that reason, Pigments is in my "fun" set up for playing around with programming, but it won't make it to my professional set up, at this time.
I currently run Pigments dry through Serum's FX block which can be run separately from Serum. It sounds great. I love the workflow of Pigments, but it still sounds strangely monoish as opposed to stereo. This makes it a toy for the time being. Nevertheless, it's a fun toy.
Improvement? I don't think the engines will ever be able to be panned. For that reason, a stellar FX block would fix the problem. Currently, the FX module of Pigments is grossly inadequate. That is, in my subjective assessment.