glsp wrote:
iPhoto was replaced in the Dock with Photos, and after opening the new app, I can no longer access my iPhoto library either by opening iPhoto, nor in open file dialog's where my iPhoto library previously was always available. That's a pretty forced transition. Your comment is not a helpful addition to this discussion and the problem at hand.
Then something is broken on your Mac. I have both iPhoto (with its library) Photos (with its library) both running on Yosemite. I'm not forced to use either one.
If you had not updated iPhoto prior to 10.10.3, then iPhoto will not open. There is a way around this, but you seem to indicate yours does open, it just cannot find the Library.
You also seem confused at what the Dock is designed to do. It exists to have your most frequently used programs available for quit access. All of your Applications are in the Applications folder. You can place any of those in the Dock so that you can access them quickly. You can also remove things you don't use.