This might be the best paper I've read describing a Tertiary bird. Most simply note a few 'key' areas of the skeleton, provide a small image of the skeleton, and at most include a tiny morphological analysis of a few taxa. Nesbitt et al. actually describe the morphology in depth, include detailed figures of the skull, pelvis, etc. and use a large analysis with many living and fossil cypselomorph OTUs, molecular characters and several potential outgroups. If more workers follow their example we might get neoavian phylogeny worked out sooner than later.
Have you noticed...-- The first author has never, AFAIK, worked on birds before, but has recently published a seriously big phylogenetic analysis and has previously published several in-depth morphological descriptions of Triassic animals. -- The second author has published on penguin phylogeny and IIRC descriptions of new Paleogene birds, but is also familiar with other dinosaurs. -- The third author has worked on Mesozoic birds and the origin of birds, is a former student of the man who authored the publication that introduced phylogenetics to the study of dinosaurs, and is deeply involved in phylogenetic nomenclature.
None of them is a mainstream paleornithologist... I hope they transform the field.