The answer is yes. A simple assembly can mount a common 60W equivalent bulb on the headband. It doesn't have any glare. It's brighter. The mane problem is it's heavy. The heat sink gets hot when running at 8.5V/4W so it's not going to get lighter without getting dimmer.

At 8.3V/2W, it still makes a lot more light than the 3.5V COB  without the heat sink.  Past headlights use a 60W equivalent bulb at very low power & no heat sink.

The biggest gains in brightness are going to come from daylight bulbs. A lot of light is taken out to make them yellow.

These Feit daylight ones have chips that run on 16V.  Sepic converter it is.  The dollar store no longer has daylight bulbs. 

These maxed out at 16.2V/2.7W before temperature without a heat sink started cracking 45C.  The voltage drop in the wire was .1V. 

That was quite an improvement over the 3.5V COB light. 

The battery & SEPIC converter are massive.

The 12V batteries were an immediate failure.

Shrinking it down to 8V made it pocketable.  It should go 2 hours on 800mAh.

The lion kingdom is frustrated with its SEPIC converters.  They're big, heavy, & fragile.  They served 1 purpose for a headlight that was in the middle of the battery's voltage range.  Every other purpose would have been much better off with a dedicated boost converter.  They might be in vogue because of solar panels, since that voltage varies much more than a battery.

The trick is all the boost converters are similar size to the SEPIC converters, so there's little advantage.  Boosting just seems to require a bigger inductor.