The verb-derivative “machine” of Latin, by which scores, and even hundreds, of semantically and morphologically related words can be built from a simple (primary) Latin verb. While much of the derivative “machinery” involved, here, is not a living part of the current English word-formation system, it is highly relevant to the understanding of the Latinate vocabulary that is such an important and large part of our total lexicon (vocabulary). And, today’s English speakers and writers feel quite free to form quite new words by analogy to the Latin words already in use, even though they may not understand the actual structure of the imitated word. Base on this point, are the endings –tion or –sion or –tive or –sive, strictly speaking, the true formative suffixes?
I think the most we can say is that they can be. If we take the word decoration, it’s a noun made from the free morpheme decorate, a verb, and the bound morpheme -tion.