Regarding the issue of color non-uniformity. Personally, given all of the strengths of this projector, I am not too caught up in it because I can only see it on uniform gray and white test material. On normal program material I have never seen it.
My previous projector was a PT-AE3000U. I had some reliability problems with it, and as a result I had purchased the Service Manual so I could look up and order replacement parts like fans and temperature sensors. Anyway, I was looking through the manual and found some interesting information with respect to "Color Unevenness". Apparently Panasonic tackles it in two ways: with a lookup table of correction data, and with mechanical adjustments of reflectors for R, G, and B. Fundamentally, the engineering challenge remains in the newer models...they are still 3-panel LCD projectors.
Under Fair Use Doctrine, here are some image captures from the PT-AE3000U manual as an FYI.
I have to wonder about the validity of the correction table once anyone has replaced any of the parts or made any adjustments to the reflectors.
The fact that there are mechanical components involved in the adjustment of color uniformity certainly speaks to how color uniformity could change with temperature and aging of components.