This kind of research should be encouraged further because old taxonomic paradigms must be systematically reviewed based on new genomic data.
I am also not very convinced with the placement of Nanoarchaeota. It seems like this phylum is moving around with the addition of new sequence data (for example in Rinke et al. Figure 2 tree, they are on an entirely different branch than Euryarchaeota). Though the authors also rightfully point out that the reduced genome size may have something to do with this placement.