Wi fi issues!
The same things you described also apply to my case!! I expected that new radio or kit kat kernel would solve wifi issues of my nexus 4 but nothing. I have tested also various kernels-roms-fixes but the result is always the same. I compared every new configuration with my nexus 7 2013 and it feels disappointing!!! wifi speed 1.5Mbps for Nexus 4 10.5Mbps for Nexus 7! The only thing I have noticed is that I can achieve 10Mbps also with nexus 4 when I change small settings such as set to 2.4Ghz channel and disable wifi battery optimization.. Speed is improved instantly up to 10Mbps but it works only for some minutes. After that it is the same bad speed / bad signal reception / weird behaviors among different routers!! nothing of these happen with samsung phones!!
Almost bad signal reception also applies to my Nexus 7 2013 depending on the router!! I am very dissapointed with nexus devices! I bought them mainly due to the fact that google used to support its products.