In fact there is a few more powerful brushed motor at that size. One of the most fearsome one are astro cobalt motors reaching 85 to 88% efficiency iirc.
The astro cobalt 90 is said to be able to replace a .90 glow engine on a plane... 1500-1600 watts continuous which is near a neu 1521 but at 2 pound. The good point though is that controller handling brushed motors are more robust...
Those are a bit more powerful, but the dewalts are one tenth the price.