I'd rather remove them completely. The wording is not the real issue.
It's more that
a) They are not specified by XEP-0045.
b) They are in english. Our client allows to switch the locale at runtime, so the end user at least expects that these messages are localized.
If a client is interested to inform end-users about such states, a client developer could use status codes as described in XEP-0045.
If nobody has reservations against, I am tempted to file a bug in the issue tracker.