Improve wording around partitioner selection

Given some recent community interactions on Stack Overflow, Nate McCall asked me provide some stronger wording on partitioner selection.  Specifically, in further discouraging people from using the other partitioners (namely, the ByteOrderedPartitioner).

Right now, this is the language that I'm leaning toward:

# The partitioner is responsible for distributing groups of rows (by
# partition key) across nodes in the cluster. The partitioner can NOT be
# changed without reloading all data.  If you are upgrading, you should set this
# to the same partitioner that you are currently using.
#
# The default partitioner is the Murmur3Partitioner. Older partitioners
# such as the RandomPartitioner, ByteOrderedPartitioner, and
# OrderPreservingPartitioner have been included for backward compatibility only.
# For new clusters, you should NOT change this value.
#
partitioner: org.apache.cassandra.dht.Murmur3Partitioner  

I'm open to suggested improvements.