Yeah the March 22nd Letter is part 2 of 2, with the patch notes likely being posted immediately after the letter and the patch itself within the next couple of days.

As for new raids, I'd certainly like a little more variety in that department, especially since their current plan seems to be having a single max level raid and (half of the time) having a much easier one 10 (or so) levels below the max. It would probably throw off their desired pacing by a lot, so I wouldn't expect it until / unless they want to modify itemization a bit (sidegrades) or they want people gearing up twice as fast for one reason or another.