I get where you're coming from on the Channel Positive Energy being for the party. It is however obvious from the context that a cleric should be oriented towards party assistance. How often do we send the cleric off to investigate beyond the next corner in the dungeon, or that dark alley up ahead? A ranger or a rogue is sent to scout, a pally or fighter is designed to stand toe to toe with enemies, and a wizard/sorceror is designed to blast from range, but clerics, bards, and to a lesser extent druids are designed as back up characters.
Not every character can do everything, which was one reason why I disliked the multi-class orientation of 3.5 so much. I'm running PFRPG in my home game now, and find that the players are making long term goals for there characters with the original class. The fellow who just made a cleric was amazed by the domain powers when added to the channeling ability. The combination seems to allow the cleric to do his job better, as he is able to heal the party when required, and select a good assortment of spells to deal with a variety of issues that come in any adventure. That is what the cleric is supposed to be!
I dislike the idea of optimization with respect to D&D solely because it takes away from the role-playing aspect of each individual character. I have found that many of the changes in Pathfinder are aimed at enhancing the role-playing aspects of each class, and it is this that has drawn me to start using the RPG. The domain powers, like the wizard and sorceror powers, add to the characteristics of the specific class.