Well, for the record, I for one did not invoke Mario Alinei and/or Thracian-as-Balto-Slavic.
Here I agree.

The two are different, but the Lower Danube (my definition would be: Voivodina and anything downstream to the mouth of the Danube) is geographically also part of the Balkans peninsula. However, it doesn't change anything about my points: the Pannonian basin and the Danube region is just as unsuitable for the Slavic homeland as the Balkans proper.
Is it really of any significance how the early Slavs labeled themselves, as long as they spoke the (Proto-)language? After all, the language must have originated somewhere and didn't come from thin air.
Yes, the fragmentation of Proto-Slavic language into daughter branches occured after the demise of the Western Roman Empire.
The Proto-Slavic homeland was most likely located around Belarus / northern Ukraine and/or southeastern Poland, not at the Danube. How do we know this? Comparative method in linguistics, and internal reconstruction. I mentioned before that the Slavic word for "beech" is borrowed from Germanic, while the word for "birch" in Slavic is a native word inherited from earlier Proto-Balto-Slavic (though a cognate with the Germanic one - compare Lithuanian "beržas" as well as Russian "bereza" or "береза" with English "birch" and German "Birke"). Its obvious that the Proto-Slavic homeland must have been located in an area with birches but no beeches (which, again, is compatible with the Milograd culture).
Also, to play Devil's advocate, in his geography, Ptolemy (mid 2nd century AD) mentions an ethnic group in ("European") Sarmatia, called the Sauaroi (Σαυαροι). While I concede the name is only somewhat similar, its worthwhile to note that they're at the correct place. and they're more or less at the correct place.
I don't see anything diagnostically Slavic about the river name "Drava". As far as I know, it is "Old European" in origin, and has parallels elsewhere (the Treve in northern Germany is the Germanic cognate, for example).
Nonsense. The term "Vlach"/Wallach/Welsh was originally the designation of the Germanic peoples for the Celtic peoples (it is indeed derived from the tribal name "Volcae"), but was later re-applied to Romance speakers.