The only real missing piece of pacman is that there is no distinction between a feature and security / bugfix update. But then you should be more stringent with upstream to beta test their feature releases better.
Really if you wanted to automate pacman nothing stops you from creating your own custom repo as a gateway to some workstation or server cluster you have and setting it up to use your custom repo exclusively for all packages. It has delta support, does checksums, uses the best compression format available, and is a lot easier to use for custom applications than the OBS or alternative packaging tools.