I disagree, I would find this a useful feature. However, perhaps my example was reductive.
The use case I have in mind is deleting feature branches. In our organisation, branch names follow a standard pattern of ACME_0000_FeatName, where 0000 is an issue number, and FeatName is a brief description; for example ACME_1234_SomeFeat.
When deleting these feature branches, a more accurate example of the log message entered may be:
"Deleted the ACME_1234_SomeFeat branch. Merged to trunk in r5679. (Acme #1234)"
As I hope this example demonstrates, the why is included in the message.
The reason for the request is that ACME_1234_SomeFeat doesn't really flow off the keyboard, so I usually copy/paste it from the "Remove ACME_1234_SomeFeat" textbox.
This is really the only scenario where I routinely find myself deleting folders using the repository browser. If I were to delete this folder from, say, a working copy of the branches parent folder, the log message textbox would suggest the name of the folder, as it would the name, or path, for any affected files, or folders. However, this behaviour, and the "Paste filename list" context menu item, to which Kalen refers, does not appear to be present on the commit dialog within the repository browser, being limited only to the commit dialog for a working copy.
Thanks,
Chris