The Debian community will know that squeeze is version 6 and sarge is 3.1. Similarly the Ubuntu community will know that natty-narwhal (natty) is 11.04 and hardy-heron (hardy) is 8.04.
If I asked a question about Windows 6.1.7601 or 6.0.6002 would you know which is on topic ?
The important thing is that their respective communities know what they mean. It's not broken so don't try and fix it.
I did some research
The people over on askubuntu.sx have both sets of tags but prefer the numbers. Checking the ubuntu* tags here on SF we have all the main descriptive tags synonym to numbers already.
Debian is slightly different in that most of the tags are descriptive. There is debian-5.0 which should probably be synonymed to debian-lenny and there is debian6 which should probably be renamed debian-6.0 and then synonymed to debian-squeeze
Other stuff to do to make things consistent
This would at least clean things up and make things consistent within the parish of debian who seem to prefer the descriptive names.