Automattic will probably be much more effective at handling Tumblr since they have experience with content platforms. Whereas for Verizon, Tumblr was way, way outside their core competency. It was always a shame at how Verizon seemed to mismanage Tumblr so it's exciting that Tumblr may become relevant again!
Wordpress doesn't seem to ever have been able to push into the "social" discovery space. I bet Automattic folks have a bunch of half-baked ideas that didn't make sense for Wordpress but would be great directions for Tumblr. Seems like they were able to "buy low" so-to-speak and get access to a whole landscape they not only competed with but couldn't have afforded.