It's no wonder they can't deprecate ntpdate, they seem to be unable to just "make it work" with any of the replacements.  I bet in 2020 we'll still be rocking the ntpdate no matter how hard they try to get rid of it!  It's good to know none of the rest work, as we've got:

https://github.com/puppetlabs/puppetlabs-ntp/pull/119

To allow it to autosync with ntpdate.  If this is something you guys would find useful I can fix the failing tests on that, get it merged in, and get an ntp release out on the forge so you don't have to think about this one again. :)