I don't see the elevated upper midrange as spiked, but more that it's is slightly elevated. There's a dip right at sibilant sounds, then it raises back up around 10k, which will give some people a sense of things being a little bright. My ears hear it as very extended.Wow that matches my impressions almost exactly. I'm curious whether most people hear them this way, especially concerning the 5k peak. As a mids-head, that peak is my biggest issue with the P1.
I personally think the Pinnacle has such high resolution, the upper midrange lift and slight bass/mid bass emphasis gives them a neutral-ish sound with added dynamics and a welcomed energy to the midrange that I find rather enjoyable. YMMV