How should I observe a dynamic set of attributes so that observers get fired any time an attribute is set or changed?

I'm relatively new to the Ember world and have run into a snag.

I've got a search grid with a variable number of filters (set dynamically) that can trigger a change of the search results. Because the filters are set dynamically, I won't know their names (and can't set properties on my controller which I would then observe).

I've set up a JSBin here that shows what I'm attempting: http://ift.tt/1AwXapu

I'm wanting to have the filterValuesWatcher observer log to the console when any value is set on the filterValues object / property. In essence I'd like to have an observes('filterValues.*') in effect.

Any suggestions on what I'm missing?