Alaric - 'Roman Officer'?

[Nathan Ross]

maps with frightening sharp pointy ethnic labels burrowing into the soft vitals of the Roman empire which could have been drawn in 1900

Yes, they do still turn up pretty frequently! - Bryan Ward-Perkins includes one in his 'Fall of Rome', just to make fun of it, but I think he points out that it's difficult to explain movements of armies and 'peoples' without maps and arrows...

some distinguished Late Antique historians use "uncontrolled immigration" to market their books. 

This is often mentioned (by other historians complaining about it), but I haven't come across many actual claims of this sort recently; it seems to be a bit of a chimera, but perhaps I haven't read widely enough into the subject.

Kulikowski has suggested a couple of times (including in the interview above) that Peter Heather is a sort of revenant of 19th-century volkswanderung thinking, but from what I've read of Heather's work he seems very keen to deny anything of the sort.

Who are you thinking of?

Guy Halsall can still find quotes from recent scholarly books about the legions leaving Britain to "shore up a crumbling continental empire"

That's from Worlds of Arthur, isn't it? From what I can see (I've just had a look at the notes at the back of the book and checked!) it seems to be from a 2003 essay on vernacular Latin by A. Orchard - that Halsall had to dig that far to find something suitably unreconstructed suggests that these views might not be all that common nowadays after all!