Just because it's simple it doesn't mean it can't be efficient.
My switching regulator circuit had the same three simple parts for the oscillator. The only difference was crude voltage regulation was achieved by adding a transistor to ground the base of the switching regulator when the output exceeded a certain voltage set by a zenner and potential divider.
The problem is the choice of core, ferrite suppresion beads probably won't be very efficeint because they have a very low Q. Don't fordet they're actually designed to dissipate high frequency signals not store energy.