WordPress by default, should include a checkbox option where we can mention that widget is for homepage or post page. This can be done by plugin developers but we cannot expect it from every one of them. Isn't there any way WordPress can enforce this option?
Widgets on homepage are required for a better visibility of the blog, whereas, widgets on the post page can be specific to that category. If we have selective widgets, we can make better utilization of homepage or post page spaces.