But as far as I read, the PI can still not boot over Ethernet, which is a requirement for me to boot into backup cycle (Installation = Restore), and it still can not wakeup on LAN.
If you load U-Boot onto an SD card, the rPi can be configured to use that to boot over Ethernet. It's not a completely "pure" network boot, but that's impossible given the hardware. (There's simply nowhere for a bootloader to live besides the SD card.)
You need some sort of bootloader, even in a traditional PXE boot scenario... it's just that your BIOS hands off to the bootloader on your onboard PXE chip instead of to your OS's bootloader, etc. So, it's chain-booting no matter how you slice it.
You can setup your SD card to have U-Boot and not much else... just what's necessary for U-Boot to, well, boot. Then it takes over and does it's network boot of your full OS. So you can get a sort-of PXE boot setup.
(No idea - my applications for the rpi don't depend on it being a speed demon on the network.)