2.4: "you'll have to wait" (src)
The Blizzcast is now out and we are working on compiling information on the Under Development for patch 2.4 to give everyone updates. It takes some time to do, but we will be updating before long. I'm sure what everyone is really waiting for are the actual patch notes, but you'll have to wait for those to hit the test realm.
Arena: no date for season 4 (src)
We haven't said as of yet, so no one will be able to answer on season 4 start date. Sorry.
Bug: Skullocs Soul (src)
There is a bug preventing players from looting Skullocs Soul, we are aware of it and a fix will be included in an upcoming patch.