I noticed this on both of my MU upgrades.. a few of the blogs do not show the blog anymore, instead they show what I have as home.php for the home page of the site.. I did a little checking, and the one blog is using default as the theme, yet when you go to http://allpagenorth.adultwordpress.com/ it just shows up like my MU custom home page.
This blog is obviously made by a spammer, and will soon be deleted, but I am leaving it for a few days so we can troubleshoot this issue.
Looking into the the blog, it appears to have no posts, just the original hello world and default comment. Not sure if this has anything to do with the other blogs using default working fine.
I did a search to see if this ha been brought up already, but searching for terms like "upgrade home.php front page" obviously bring up a ton of unrelated stuff. I apologize in advance if this has already been been discussed, I did go through several forum pages looking for it.
I also just noticed that a blog that was using the Anthurium Mix theme no longer shows the theme, just plain text on that blog.. is there a list or wiki list somwhere that has been / we could set up to point out the themes / plugs, etc.. that no longer work with current and future MU upgrades?
Much appreciation to the entire wordpress team and community BTW!
Steve