Moving to the user list.
The new restrictions were added as part of CASSANDRA-1377 for 0.6.5 and 0.7, AFAIK it's to ensure the file names created for the CFs can be correctly parsed. So it's probably not going to change.
The names have to match the \w reg ex class, which includes the underscore character.
Now that we can make columns families on the fly, it gets interesting to use
column families more as part of the data model (can reduce diskspace quite a
bit vs. super columns in some cases).
However, currently, the column family name validator is pretty strict
allowing only word characters and in some cases it is pretty darned nice to
be able to put something like a "-" inbetweenallthewords.
Any reason to be this strict or could it be loosened up a little bit?