There is a time for generating ideas, and there is a time for choosing them. We sometimes get these confused, or conflated.
Idea generation is typically best done early in a process or at the beginning of a new iteration. This can be an individual or group process, but you should not mix generating ideas with selecting them. We don’t do a great job of shifting back-and-forth between creating and critiquing.
Once you move into idea selection, you are narrowing down ideas until you choose what is considered best. You may merge multiple ideas into one, but the goal is to reduce your options down to one.
After you have selected an idea, don’t “change horses” flippantly. If you’ve set a course in one direction, your team may already be making plans and doing work they feel is valuable. If you continually change your mind, they may feel like you are pulling the rug out from under them. This will make it hard for them to commit themselves to projects, especially if they don’t feel like you’re committed.
It’s OK to move the rug. Just make sure no one is standing on it when you do.