Why does the FJ400 Strobe have an extended bare flash tube with a dome instead of being recessed and covered? Is there an advantage to having an extended, bare bulb flash tube?

The optimized positioning of the extended flash tube, combined with the bare bulb and dome of the FJ400, create a wider, more even spread of light that is ideal for filling light modifiers. The covered tubes or non-optimized positioning of the flash tubes (recessed flash tubes) of many other strobes can create an uneven light pattern and hotspots. Those strobes may not fill modifiers evenly or adequately in order to take full advantage of the softening effect created by the larger surface area of your modifier.