A smart duplicate text finder, that can find block

A smart duplicate text finder, that can find blocks of text such as full sentences or say 80% same - needs to have selectable match value from 50% plus. Needs to present matches to allow for easy deletion of the block you don't want to keep. Duplicate text can arise where you create entries in more than one doc and merge them later, or add to a note made earlier, while having a second copy you may edit and add to also. You finally want to create a unique all inclusive doc with no duplicates - hence the need for good duplicate finder. None of the features you list would entice me to get this app, but a real duplicate finder would. Plse keep me informed of your interest in this idea.