I would second Peter's comments and concerns. This issue MDL-22433 is presently mislabeled and mis-prioritized (if that's a word in English).
(1) Mislabeled: Wiki page templates "not working" is a bug, not a new feature. Wiki page templates are an old feature that needs to be brought forward from Moodle 1.9 into Moodle 2. Page templates are a very common feature found in most wikis elsewhere. From a teacher's perspective, page templates are crucial in scaffolding wiki assignments for students.
(2) Mis-prioritized: The current inability of Wiki 2 to support page templates is literally a BLOCKER (not a minor) issue. No page templates means teachers can't effectively use Wiki 2 or for me even Moodle 2.
I used Moodle 2.0+ in my writing classes during the Spring 2011 semester. While there's lots I like in Moodle 2, Wiki 2's current inability to support page templates (and groups fully) forced me to return in Summer 2011, Fall 2011, and onwards to using Moodle 1.9.12+ and wait until Wiki 2 is really "ready for prime time" before I try upgrading again. While I regret losing the ability to use Workshop 2.0 (functional enough now to use in live courses and a large improvement over a still usable [with caveats] Workshop 1.9), eWiki 1.9+ is actually more functional (that is to say, more usable and productive with real students in live courses) than Wiki 2 in its current state.
I am absolutely confident the Moodle programmers and community as they have in the past will develop solutions to these challenges. In this comment here, I'm just trying to clarify and underline the importance of wiki page templates in Wiki 2.