It’s certainly hard to argue with such an assessment, and not only because it’s coming from the dude who lived in the character’s headspace for nearly a decade.
Before viewers even see Michael C. Hall’s fully lit face, his narration kicks in, putting everybody right there in the (dark) passenger seat for his journey.
So for a show that so fully adhered to the idea of cycles being repeated, it only makes sense for the series to have ended in a way in which it began, with Dexter’s disembodied voice cluing us in on where his mind was at in that new setting, or some other insightful nugget to cling to in lieu of more episodes.