why would you think that? I mean Blizzie has failed the past 18 months to effectively fix ingame problems, partly the reason I've played for a collective week in hours the past 6 months.
DS and SoR have been weak since Cata start, has it been fixed to be roughly equal to other classes? No it hasn't. From what I hear the same old same old is happening on MoP Beta.
Realistically they need this out by November as they usually do every expansion, and it's underdone massively. You'll have classes doing 50-60% damage of other classes like where Ret was at in Nov 2010 with Cata. Classes 2 shotting other classes. nothing ever changes. Looking at Cata and the total lack of effort to balance classes as quickly as possible, so people can have fun competing, they failed miserably. I'd say that will be repeated in MoP