Doc Myers has another evo-devo post up; this one is on conserved dorsal-ventral patterning in the vertebrate and arthropod nervous systems. This stuff is fascinating, and Myers does a great job of explaining the research for a general audience. I’d imagine he’s an amazing teacher, as well. The entire field of evo-devo is really increasing our understanding of the evolution of animal body plans, with many more interesting discoveries on the horizon.
But it doesn’t really do much to explain evolution on a broader scale. Work in the field of evo-devo is mostly limited to animals, with some stuff being done in plants. Check out the eukaryotic phylogeny I posted a couple of weeks ago. Notice that animals (and land plants) make up a tiny fraction of the diversity of eukaryotes. Also, keep in mind that this tree excludes archaea and bacteria, the other two thirds of the diversity of life.
How significant can evo-devo be if it can only explain the goings on in a small subset of taxa? A far broader scope would carry much more importance — for instance comparative molecular biology or evo-cell biology. If you want to make truly meaningful comparisons, choose something that all eukaryotes (or, better yet, all cells) have in common.
Thanks to Larry Moran for bringing this up in the comments.