I don't believe That 2.0 will be Delayed at all , Its a totally different engine im guessing there simultaneously Creating the content for both Engines by some means of porting.
The new engine is supposed to allow them to do more wile the limitations of the current servers its almost like everything they release at this point is more of a test for the content on the new engine. I wouldnt be surprised if they have a totaly seperate team working on 2.0 on the side wile smaller individual teams are working on patches for current servers.

2.0 will be done by the designated date have faith and stop bitching about it , it doesnt make them work any faster