You're right in that the LEDs are very lens-like and directional.

But I don't think it's feasible to reverse them, and wouldn't help diffuse the light, it would only make the light dimmer but not any more diffuse.

You don't necessarily need incandescent bulbs to do it. I know it's possible to diffused light with LEDs, as my house is full of examples of plain-old directionally-biased LEDs being properly diffused by this milky white plastic stuff I've been describing all along.