That's why I go to Healesville more often. It takes a similar amount of time to wander around and I can use the other half of the day visit a winery or something. What else is there in Werribee? The drive out to Healesville is nicer too. And I have a car.
Healesville is a nice drive, and there is quite a bit to do out there (although I don't like wine). And there's a more diverse collection too! Werribee has a couple of attractions nearby, you can wander round the adjacent Werribee Mansion and gardens, or go down to Serendip Sanctuary.
Or the western treatment plant to see birds. Also, there is the Fairfax winery out at Werribee too, as well as the Mansion.
Yadumu (Yakini) the gorilla recently celebrated his 14th birthday: http://www.zoo.org.au/news/happy-birthday-yakini
1.0 cheetah Kaidi (b.2003 at Monarto) has died. This leaves Werribee with his brother Inkosana: http://www.zoo.org.au/news/cheetah-will-be-sadly-missed
The last news for 2013 was that the hippo calf was sexed as female and is now on public display: http://www.zoo.org.au/news/baby-hippo-on-display
Not major news that warrants a 2014 thread but it appears that Tombo and Tonyi the male lions have had hormone treatment so that they can be housed with Jarrah the female without aggression, however, that means that they have lost their manes.