Unfortunately, it seems from recent documentation that the previously planned CBD enhancement from Eveleigh to Wynyard and beyond is to not proceed. This is a decision which means that there will not be much improvement in Cityrail for decades, particularly for the Western and Northern Lines.
Giving the Western Line its own path through the CBD would be best practice. It's the busiest line on the network, and busier than the North Shore line (counting the upper Northern Line), Illawarra Line and Eastern Suburbs Line all of which have their own path through the CBD. So why not separate the network out further which will help with allowing more and stricter sectorisation? That would get these passengers out of the current Town Hall and Wynyard significantly easing platform congestion and the new platforms should be able to be built wider than the existing platforms. Alternatively with what is known as bifurcation which means that there would be 4 additional platforms per station to reduce/remove dwell time in the CBD from being the capacity restriction. This would leave Parramatta dwell times as the limitation.
The above linked documentation mentions some restrictions which are either soon to be removed or can be. Numbers 3, 4 and 9 can be easily removed, they just choose not to. In the case of number 9 which the document details removing this does mean trains need to take a slower path, however, this limitation is solved by the CBD enhancement (formerly called the Western Express) as described above, as is number 7.
Such an unceremonious dumping deserves an explanation, however the linked document above seems to be an attempt to deflect the criticism rather than explain it. It does not refer at all to the plan to increase CBD capacity along the "Metro West" alignment as originally planned, but an alternative plan which had never been publicly proposed involving a Cityrail expansion along the "Metro Pitt" alignment, which would not help the Western Line.
I just wonder if they are pushing some agenda, and if so then what? Perhaps it is just to be different from the Keneally government's sensible Western Express plan.