Ignore domain appears as an option if you click the domain name within your feed or global pages. The reason it's not on the main page is because it's already too damn crowded with three tags, user options and follow domain option. Can be fixed, however.
No disagreements here. I think the more we can do to help people curate their experience, the better. Where there is a follow, there should also be an ignore. Make sense to me.
I wonder if it might work better to have follow/ignore options for each element as a popup when you click on the element. That might look a little more elegant and allow for more controls. As it is, that top line is already encroaching too far to the left for my taste, but I agree that having both options is better for functionality.