While it would help relieve the rail services, it's so much less efficient that it can only be regarded as a stop-gap until we get meaningful improvements on the rail line.
They can use the emergency stopping lane as bus lane, all you do is to change the sign.
Looks as though there will be many sections along the freeway where they will no longer have emergency stopping lanes after they finish this upgrade.
Any kind of express service from these outer sprawl suburbs to the CBD would not help to acheive significant change in modal share from road to rail for the reasons stated at this link, to do with where people work:
Basically, out of 110,000 workers in the Greater Dandenong-Casey-Cardinia region, only 8,657 people in 2001 were employed in the Melbourne CBD, with the majority of potential rail passengers being employed within the region, or in other parts of the S.E. suburbs.
Although the population of Casey in particular has grown significantly in 7 years, the percentage of those employed in the CBD would not have changed significantly.
Remember - only 15% of Melburnians visit the CBD on a given day, a figure which would be less in suburbs 30+ kilometres from it.
In the forseeable future, there is no hope of ever seeing an express bus service along the Monash Freeway. Stupidly, the government at the time when Citylink opened up, made an agreement with Transurban, the operators of the Citylink tollway, that if the government was to implement any projects or public transport services that would greatly effect the number of vehicles using Citylink, and thus reducing Transurbans profits, Transurban would have an avenue to seek compensation from the state government. With this clause in mind, it acts as the basis of why the government to this day has ruled out any possibility of committing funds to an express bus service.