Yes, Apple has restored the ability to set a user and system umask in OS X 10.10.3. This is a huge fix for users of shared storage. Xsan and all SANs where users want to be able to share files, projects and all things without using ACLs or any LDAP directory. This is great. I am jumping up and down. So happy. So many people wanted this. Anyone using shared storage have been demanding this since the upgrade to Yosemite. 10.10.3 is out today and we will be happy.
sudo launchctl config user umask nnn
sudo launchctl config system umask nnn