I just got my P1D CE a few days ago. Let me say I was surprised to see it rival the output of my Surefire C2 and G2z on fresh batteries. It seems to throw about the same. I still wouldn't use it for "tactical" purposes, as it has no tailcap switch, but it is very bright, and on the low mode still useful. On medium/primary mode, it is visibly brighter than the original P1 3W and has a slightly longer runtime. Running it on high, it doesn't get as warm as the P1, either.
I'd say it's definitely an improvement over the P1. I can answer any questions about the P1D and P1D CE or other Fenix lights that you may have, as I have them all sitting on my desk.