I do agree regarding the charging "Device off" issue, but I tend to never switch my device off, so I can live with that. For the rest I do not recognize any of the issues you listed. 3G / 4G working fine, WiFi also and no problems with the hardware buttons.
By the way, mine is also HK version. I bought during my last trip to HK last year.
I tried PAC Rom, and had no major issues either, except missing Recent Apps manager. Didn't try any other ROMs up to now. I tend to prefer "basic" ROMs and add some needed stuff through Xposed. This is also the reason I decided to switch to CM11 when it became official. Haven't found the need to come back to PAC Rom since. It's not TOP but does the job for me. As you are speaking about battery, I do easily get 4 hours of Plex Video Playback over WiFi at decent screen brightness / 4 to 5 hours video Playback with MX Player and video stored on external SD-Card. Will however probably revert to TW ROM as soon as a 4.4.2 version is released to recover PEN functionality.
Did you use the official CM11 from their website? I know that there are older non official versions around (which I initially tried but had problems with).
I attached a screenshot of my about screen so you can have a look at baseband and kernel.