Not sure exactly, full includes more apps and features. You can examine the different make files in vendor/cm/config. The option is selected in device/lge/thunderc/cm.mk.
Also you can drop the extras folder inside the rom zip into the system folder to integrate the extras into the rom. As far as todo stuff, I was thinking about trying to configure the rom to use bluez instead of bluedroid in hopes that it would fix bluetooth, just haven't gotten around to it. Wireless tether needs fixing. MMS, maybe voicemail notification. There may be some power management issues which are kernel related, sometimes my phone goes into a kind of 'sleep of death' and doesn't want to wake up. Also power management optimizations for lower battery drain. I can't seem to get SELinux configured, not sure what the problem is, may be kernel related. Zram and/or swap might give better performance, but will probably be implemented by androidarmv6 if feasible. Building with the Linaro toolchain might give better performance.