1.3.1 A Radar Control Service may be provided to aircraft operating IFR, Special VFR or VFR.
When providing the service controllers issue instructions to which:
a) pilots of aircraft operating IFR are required to comply; and
b) pilots of aircraft operating Special VFR or VFR will comply unless they advise the controller otherwise.
HeliComparator,
If I understand correctly, your clearance was to transit VFR via the threshold. That means the navigation is up to you, as well as the separation from other aircraft. If you need to adjust track to avoid another aircraft, there's nothing to stop you doing it. If the controller wanted you to follow a specific route or track, he would have issued you with a heading or a restriction (e.g. fly no further East than the Mxx motorway). You are then responsible for advising if at any time you can't comply.
I think you are getting too hung up on the words Radar and Control. It's Radar because surveillance is available and this can be used in a manner of different ways as detailed in a previous post. It's Control because you are no longer outside Controlled Airspace. Control does not necessarily mean rigid though. It can be done with a light hand by using level blocks (e.g. not above/below a level) or general routeings (e.g. via a VRP or an Entry/Exit lane).
If you don't think VFR and 'self separation' is a good thing, think about what the alternative would be. A rigid IFR type system with Controlled Airspace entry severely limited as the controllers would have to provide positrive separation between all aircraft. That would severely limit the capacity of many Class D areas and result in lots of refusals or delays for transit aircraft. That's not a road I would like to go down, either as a pilot or controller.