The formula for 2.4 was predictable based on what SE has done so far.
New tomestone
New Coil
New primal
2 HM dungeons
1 new dungeon
2.5 content is also predictable.
New CT
New primal
2 HM dungeons
1 new dungeon
Though I don't know what primal they would do after Shiva. Perhaps that Odin trial people were talking about?