By now you will know my views on free speech, Phil. It may be inconvenient and it may be annoying but its best to know where the idiots are and to know what they are thinking. I would therefore suggest that this site could be improved by never deleting anything and never banning anyone. If we cannot defeat pillocks by reasoned argument then it is time to give up.
Having said that, I am aware that there are limits to free speech. If it doesn't keep within the law then you, as site owner, can be liable to prosecution. But I suggest that few of the previously deleted threads or banned members have breached the law. On the plus side, since the demise of Cassandra, there have been fewer such problems. Keep going in the right direction.