Siebrand, one of our i18n overloards, is stating that some wfMsg function has been deprecated here: https://gerrit.wikimedia.org/r/#/c/17055/4/SRF_Utils.php
However, the functions do definitely not have any deprecation notice. Do we want to deprecate them at this point? If so, @deprecated and wfDeprecated should be added. And if not, it's probably still good to mention using the newer methods if your code can depend on 1.18 or later in the function docs.
The deprecation notes come from the mw.org page on wfMessage [0], so unless that page is incorrect, those functions have been deprecated for some time. In fact, several patches have gone by my screen about making this specific change (including one you merged [1]).
This seems like it's already been decided, unless I'm mistaken.
[0] http://www.mediawiki.org/wiki/WfMessage#Comparison_with_the_deprecated_wfMsg... [1] https://gerrit.wikimedia.org/r/#/c/16043/
(oh, Krenair beat me to the 0th link, sending message anyway)