It would be helpful to have a preference to allow merging into synonyms, this would enable only those members who find they need to do this to enable it.
We are finding that there are often cases when we want to merge two taxa, and one is a synonym. If we are merging the synonymised name into the non-synonymised name, there is no issue, the sytem allows this. However we sometimes need to merge the non-synonymised name into the synonym, in this case we have to de-synonymise the name, perform the merge step and then synonymise the name again. This leads to several extra steps and creates the possibility of an error being made with the name being incorrectly synonymised following the merge.
We have not yet needed to merge two synonyms, however this may be needed. In these cases there could be conflicts with the accepted name which would need to be resolved. In these cases I think we would want the newly merged name to maintain the synonym of the name that was merged into, as this is the name that is to be maintained in the database. This may be overly simplifying this situation, so the user may still need to resolve these in a more manual manner to ensure that correct synonymy is maintained.