Healing is not about maximizing HPS. It's about making your party alive in any situation. So sometimes it's better to have less HPS but more mana to spend it when it's really needed (for example - Imperator in Highmaul). BTW, Hermit has an option called "Mana balance" which allows you "play" with how much HPS you will get.
If you are speaking about talents - then it very-very depends on fight. As something "neutral" I'm using that spec:
Warlords of Draenor Talent Calculator - World of Warcraft but be aware: It's only my opinion and not something like "holy truth" =)