Are you arguing for an inclusion of Italy?

[...] (Modern) Turkey is not important enough to be included, as well as modern Italy.
Not at all. The question of importance is relative, but I am not arguing for the inclusion of neither.
My point was that Ataturk's Turkey is "a different civ" from the Ottoman Empire, so I would advise against renaming "Ottomans" into "Turkey".
I can think of hundreds of other examples of violent political change with huge consequences on a state level but rarely do such upheavals lead to the end of a civilisation [...] On the other hand there is an obvious cultural continuity from the Ottoman Empire to modern Turkey. There was massive institutional change but Turkey was hardly alone among her contemporaries at that.
At any rate the OE was more widely known as 'Turkey' anyway in its own day.
End of civilization is a bit rare, I agree. Exhaustion of a cycle and end of
a civilization is more common. Formally Rome and Byzantium have no solution of discontinuity, but we acknowledge them as two civs because:
1) they occupied different, although overlapping, areas
2) the monotheism of the latter was unknown in the former
3) the multiculturalism of the former was not present in the latter, which would eventually become only greek
There are LOTS of civs coming and going, but not all of them strike it great and make it into Civ
As a small side note: in my country the Ottoman Empire was known as the "Ottoman Empire". There is a particular type of sofa which in my language bears the "ottoman" name, too - coming likely from there. Alternatively, we spoke of "The Turks". "Turkey" was not even used as a geographical definition, the options of choice being "Anatolia" for the peninsula and "Eastern Mediterranean" for the global domains.
I don't really consider any of that good criteria, especially considering it wasn't that big of a change.
I think Armenians, Greeks, Syrians, Lebanese and Kurds, between others, might disagree.
Greeks and Armenians were "epurated" - either killed (call it chaotic civil war or genocide, I am NOT making this point) or sent "home", that is, out of their ancestral lands, on exhausting marches toward newborn states which claimed the relative culture. Of course, there was a backlash against now-foreign turk communities, too.
Lebanese and Syrians were simply forgotten as non-Turks as well, but fortunately there were not that big mixed communities, so relatively less damage here.
Kurds got their own cultural identity simply negated.
It is a difficult question: if Prussia and Germany qualify as different civs(Austria is a fair bit easier to distinguish and argue for, as Prussia and Germany became indistinguishable politcally), does that also mean that Anglo-Saxon England and Norman England are different civilizations? Persia and Iran? Moors and Arabs? Manchuria and China?
Persia and Iran I'd say not, since the change was only political and religious. No change of territory or people. They did not refuse the cultural heritage of the past, like Turkey did.
Moors is a name used in Europe for the Arabs. I don't think THEY ever used it. So again, no.
The change between Anglo-Saxon England and Norman England was drastic so I'd say yes, there is a civilization change here. But I would not consider Anglo-Saxon England a civilization, just some barbarian fringe kingdom as the Visigoths in Spain. King Arthur is a later myth. I'd say that an independent English civilization worthy of this name begins precisely with the Normans.
Manchu were of course another civ with respect to China! They CONQUERED China, in fact. Afterwards they got assimilated, like the Mongols, by the more complex and vibrant chinese culture. In China, the Manchu dynasties are considered dynasties of invaders, not Chinese.