I believe I've done my due diligence looking into this problem--I saw the older forum posts as well as bug reports on the github project page for linux-raspberrypi, but I'm still left wondering.
I have an rtl8192 based usb wifi card--a couple of them, actually. They work just fine with my x86_64 arch and are using the in-kernel rtl8192cu driver that depends on rtlwfi.ko, rtl8192c-common.ko, and mac80211. I can do things like use ad-hoc mode with them and they work flawlessly.
On my raspberry pi running the latest and greatest Alarm, I see the realtek 8192cu.ko module is included. This module will let me connect in managed mode, but I cannot seem to get it to work doing anything else.
So my questions are: Why was rtl8192cu disabled and continues to be disabled? Is there a known issue with it on the raspberry pi? Can it be re-enabled? I downloaded the rpi kernel source and compiled rtl8192cu, but it would seem the dependencies (rtlwifi, rtl8192c-common) are missing and I cannot figure how to enable/build them.