Nosy mediators (or mediator-mini-controllers) open the view's mail

NosyMediator.as

// Good mediator behaviour:

function handleDataEvent(e:DataEvent):void
{
    var userVO:UserVO = e.userVO;
    view.showUsername(userVO.firstname, userVO.surname);
    view.showAge(userVO.age);
    view.setStatus(userVO.isSaved);
}

// Nosy mediator behaviour (in this case it also uses an injected model)

function handleDataEvent(e:DataEvent):void
{
    var userVO:UserVO = e.userVO;

    if(userVO.age < 10) 
    {
        view.showKindergartenLayout();
    }
    else 
    {
        view.showNormalLayout();
    }

    if(userVO.country != 'US') 
    {
        var countryColours:Array = countriesModel.getCountryColoursListFor(userVO.country);
        view.useColourSet(countryColours);
    }
}

I'm in the congregation! Mediators route. Anything else is beyond scope for me.

Excellent! Yes - keep it simple for each class and you only have one problem - how the classes work together. With mixed-purpose classes you've got two levels of headaches. In the classes AND between the classes. Ick :)