We'll see ports to the GNex by various teams soon enough, although it is a bit of a shame Google are not supporting it themselves, that leads me to believe they tried and failed to make it work properly.

That's a bit odd, though, as 4.0 works almost perfectly on my Galaxy S, and 4.3 runs "okay". The smaller memory footprint should make 4.4 work great in theory, but it might not be a memory issue at all.