Although I agree with a few things in Buckshots post (especially regarding quality of journalism) there are a few items that I think are a bit out.
Yes, Cobham do operate and maintain the 717s, however the aircraft are still owned by Qantas.
As mentioned the schedule for the 717 out of Hobart has not been released as of yet so one can not accurately predict if there will be an increase or reduction to the amount of seats or freight capability to and from Hobart when the 717 is introduced to the route.
Having said that, based on the Department of Infrastructure's Domestic Airline Activity report for 2012 Hobart was the 9th busiest airport based on passenger movements with about 1.92 million passengers (for comparison interest 8th position went to Canberra with about 3.07 million and Adelaide 5th with 6.45 million), this only accounts for 1.7% of the national total of domestic pax movements so although Hobart is a capital city I don't know if it required a "City Flyer" based service on those numbers.
The report also states that the Hobart - Melbourne is the country's 10th Top Domestic Route with 1.24 million passengers travelling the route in 2012 with a total of 1.57 million seats being provided over 9072 flights. This equated to a load factor of 79.1%. The same route in 2011 saw 1.16 million passengers, 1.35 million seats on 8032 flights with a load factor of 85.8%. This shows that just because there are less seats available it does not necessarily mean there will be less passengers on the route, and the increased load factor shows that it could mean that better sized aircraft or a more appropriate amount of flights are being used/conducted on the route.
As mentioned before the frequency of operation has for the 717 has not been announced but based on the current schedule of Hobart to Melbourne there are 410 Qantas seats per weekday, 79.1% of that is 325 (rounded up) passengers per day, if the 717 was to directly replace the same flights it would provided 330 seats per day in the two class cabin configuration with a 98.48% load factor (I know that realistically this load factor would not eventuate but if it did it would be excellent aircraft utilisation would it not?).
Of interest the figures show that 2011 had a reduction on seats on that sector from 2010 resulting in better load factors and 2012 has seen an increase in seats with a reduction of load factor again.
All of the above mentioned stats are not solely based on Qantas alone but all movements to and from Hobart, therefore my assumptions for calculations have been based on the information provided on all operations and translated into the Qantas operation from there as I do not have access to Qantas operation only figures.
Check Thrust.