So about traffic and taking it into account for routing:

in models/RoutingModel.qml, line 44 reads:

routeType: RouteOptions.TYPE_FASTEST

RouteOptions.TYPE_FASTEST translates to "1" if you print it out on the console. If I change that to

routeType: RouteOptions.TYPE_SHORTEST

that translates to "2", and I actually get the shortest route (will dismiss highways etc.).

Now I bet that the underlying code actually allows for traffic to be taken into account, my old Symbian Ovi Maps routing has an option "optimal", however RouteOptions.TYPE_OPTIMAL or RouteOptions.TYPE_OPTIMIZED does not seem to work (you get an error like "unable to assign [undefined] to int routeType" on the console).

However, when I set it to "3" manually via a property, I do not get an error. On the other hand, on some initial tests, traffic jams do not seem to get evaded either, so I am not sure what it means.

But if people want to test around, here is a patch: http://paste.debian.net/download/179798

(Setting routeOptionType to 2 instead of 3 clearly selects the shortest route for me)