From July the Q400 is programmed to take over more of the GLT/ROK/MKY flying from the 717, this was meant to happen from April, but recent crewing problems seem to have delayed things. The spare 717 capacity will then go onto BNE-TSV/ISA/CNS allowing the 737's to be redeployed. Qantas.com.au seems to have all the new scheduled loaded.
Current loads don't really support moving more flying to the 717 unless they want to fly around 1/2-2/3 empty all day. The 717 reliability has been woeful lately, especially on the J-class fleet. I don't think this has anything to do with Cobham though as I believe that they no longer do the bulk of the maintenance.
The bulk of the sectors that have been cancelled ex-BNE have been due to lack of FA's. This has given the Q400 FO's some mild reprieve.