I don't think just getting a Nexus device guarantees features that are already present and have been present in devices like the Galaxy S (all of them) and recently the One X. Sure the updates are infrequent especially in the US, but the feature set can't be beat by any means. On the latest iteration of Android, still lacks basics that 'old' phones like the S2 (more specifically the software running it) have offered for a while now, and even iOS.
Speed between a year old S2 with a slightly more recent GNex, is like night and day as is practically every other Android phone. Things like the camera, browser, settings, media management etc. It's a lot of little things leading up to a lot of big things that make the whole thing 'just work'.
So in my honest opinion it just seems to me that raw Android is the one playing catch up to the likes of Samsung, Apple and an extent, HTC. And then there is Motorola who keeps manufacturing poison, the sooner they die off the better.