re: Planetary Migration
"The difficulty of reconciling Type I migration with giant planet formation may signal basic errors in our understanding of protoplanetary disks, core accretion, or both."
Well said. Despite valiant efforts by many folks far smarter than I*, we are still too far away from unserstanding solar system formation to take our theories seriously. A far cry from the early 90s when we thought we had a better grasp on such things. Then reality intruded.
* Yes, that IS possible