I would expect the currently preferred routing of the Highway 107 Cherry Brook Bypass to look like the green routing on the image below (interchanges existing Highway 107, Lake Major Road, North Preston Road and at Highway 7, with flyovers or flyunders at all other roads). Besides the southern routing through Cole Harbour (which is least preferred due to the mass demolition it would cause - hence the red colour), I have very recently thought of a more northerly routing that would allow for a 110km/h limit on a 110m right of way with 30m median, assuming 4 traffic lanes are built (citing new Ontario high speed highway right of way standards), with proper interchange spacing (directional split interchange at the west end, interchange at Highway 7 near East Preston, interchange at North Preston Road and an interchange with a connector to Lake Major Road, where the connector would be near the green route and I would have the connector built to the same standard as Wright Avenue in Dartmouth Crossing, and flyovers/flyunders at all other roads).
The northern routing could also support the construction of a high-speed semi-directional ramp system to Highway 118 once traffic volumes warrant such a connection (save a right of way for it and keep on using the existing ramps to the 118 for now). The existing Highway 107 near the Montague Mines interchange has curvature that is a little tight for a 110km/h limit, and it barely meets the specs for a 100km/h limit, unlike Highway 118 which has very straight curvature (except at Fall River) and yet, its limit is only 100km/h.
Keep in mind this road could be intially built as a two/three lane tall wall divided road (one lane each way with a jersey barrier in the middle, with 3 meter wide paved shoulders with two 2km long passing lanes in each direction (on the yellow routing) or one 2km long passing lane in each direction on the green routing (they would alternate near the middle of the route). Think of a highway with alternating passing lanes, such as what is shown in the following link, but with a 4ft high tall wall barrier between the opposing traffic and with the right lane merging into the left lane (unlike having the left lane merge to the right as shown in the video):
Website the Youtube Video originated from (Missouri DOT):
As an aside, my suggestion would be a very quick and cheap way of sorting out Highways 101, 103, 107, and Highway 104 east of the Antigonish Bypass construction zone (and its eventual extension to Sydney). Then get the undivided, rumble-stripped version of this going along some of the trunk and secondary highways that are not paralleled by a 100 series route, but that have significant passing demand.
For the red routing it would have to be built to 4 lanes tall wall divided with an additional third lane in each direction that would act as a general auxiliary lane between an entry ramp and the next exit ramp and as a bus-only lane between the exit ramp and the next entry ramp.
From what I have seen lately in Cole Harbour, I believe the new highway is justified (high amounts of southbound left turns and westbound right turns). An interim measure would be to build a roundabout or a "Continuous Flow Intersection" at the Main Street/Forest Hills intersection.
Continuous Flow Intersection:
I often refer to a CFI as a Mexican Left, since its design originated in Mexico City, and it has helped a lot in areas where it has already been used. The Greater Toronto Area could really use a bunch of these on its arterial grid roads. For HRM? Try it as an option for Sackville Drive at Beaverbank Connector in Sackville, or if you really want to be witty, suggest it to HRM for the infamous Willow Tree intersection in Halifax (Robie/Quinpool/Cogswell/Bell).