Yes, it feels a bit more like open-source.
If only those "firmware" could feel a bit more like ditributions, with real package managers. Each package could have its own life instead of only beaing seem as a part of a whole blob.
What would be the point ? Updating involves a complete overwrite of the system instead of just replacing a component. I don't know if it's the case with cyanogen (I don't own a cyanogen supported device, my handset is a samsung spica that has is own, very chaotic, community).
I know it's not impossible,usual Linux distribution are already very good at this (actually, I just replaced the firware of a low-end NAS with 64Mb RAM with Debian Squeeze), but I suppose it comes from the form of the original Android code drops, that were kept by the communities.