I think these reasons are why the phpMyAdmin package will probably go away. There are too many upgrade issues to keep up with to make it worth packaging.
Correct. This package was requested and produced, however there has been very little feedback about it. The phpMyAdmin folks seem to change things very rapidly and I do not feel overly comfortable with a package that changes this often being moved to centosplus. The dev.centos.org repo is meant to be a testing grounds before packages move to centosplus or Extras, and as such, if phpmyadmin isn't going to make the leap, there's no need to maintain it in dev. Unless people provide feedback about the package, or show some overwhelmingly stellar reason why it should continue to exist, I'll probably remove it soon.
-- Any sufficiently advanced technology is indistinguishable from magic. -Arthur C. Clarke