TBH I wouldn't mind paying £400 that price if it ensures a kick ass camera and great battery life, it already has the best software (for me) and will have a nice design, build, screen, SoC, just want that camera too be top notch.
To be honest I would rather they had sacrificed the SoC and put in a cheaper one and went all out on the camera. We have hit a stumbling point on SoC's in phones where it doesn't matter that it has more power, it's performance will be limited by the cooling and throttling in the phone.
You can see this in benchmarks of phones like the Moto X where the benchmarks are very close or equal to far more 'powerful' phones because the SoC's in these phones are being throttled.
I think they could have even kept the exact same chip as the Nexus 4 in fact, improved it's performance with better thermal cooling and added a kick ass camera, more storage and a better battery.
Will have to wait and see exactly how everything works out for the N5, but it's a shame manufacturers are forced into jamming these OTT chips into phones without adequate cooling just so spec whores (there are some on this forum who moaned massively about the SoC in the Moto X) and reviewing tech sites are satisfied.