I also think that dinosaurs would benefit from more lumpin'. It seems as if dinosaurs are being treated by dino-specialists as exceptions to the rules of taxonomy.
There are no such rules. The only rules there are are of nomenclature, not of taxonomy, and they almost make a point -- _taxonomic freedom_ -- of not defining the term "genus" or even "species".
I think some of Greg's lumping is defin[i]tely feasible as it brings dinosaurian taxonomy closer to that practiced by other workers who deal with other taxa (invertebrate and vertebrate). that's my 2 cents.
It is a common claim that extant mammals and birds are laughably oversplit compared to extant insects, for example. There is no standard, there is no general practice. Genera (or taxa at any other rank) are not comparable; they are therefore not countable -- any attempt to count them can only yield a cross-section through the personal tastes of particular taxonomists at particular times --; and that's why biodiversity cannot be studied by trying to count orders, families, genera or even species.
To study biodiversity, you can't simply read up on taxonomy; you have to do science. That's more work, because you need a phylogenetic tree with dated nodes. Search the archives for the Phylogenetic Diversity Index.