There was recently a consultation period about removing the 613, 614, 615 and 616 bus routes from Epping Rd and sending them via Lane Cove Tunnel (which would append X to their number). This is a welcome and overdue change.
This also represents the last of M2 to City services going to the Lane Cove Tunnel in peak hour. However, outside of peak there is still the half hourly 610 which goes via Epping Rd. The best solution here is to merely extend the M61 to Rouse Hill along the 610 route and run the 612 outside of peak where justified. Perhaps this will eventually happen. Without the M61 it seems like there would be little in the way of service outside of peak hour between Castle Hill and the CBD.
A related question is what of STA services to the Macquarie area? Currently the peak only 293 and 297 services are the only services which use the Lane Cove Tunnel. Why is the 288 (QVB to Epping via Coxs Rd and Macquarie) not in this list? The whole part along Epping Rd through Lane Cove would still be served by the 292 which has similar operating hours, and trips could be added to the latter with the money saved by the faster operation of sending the 288 via Lane Cove Tunnel. Even the Epping to Lane Cove service is provided by the 290.
The service planning does seem to have a lot of inertia.