It's a different kind of difficult to get to. Not sure anyone other than Windrunners could reliably stay in a highstorm long enough to recharge themselves instead of just spheres, and the storms are on a calculable timeframe (not to mention that the spheres represent a finite resource that can be stolen, since they can't be Soulcast). If you can separate the spheres from the Radiant and/or the Radiant from the Honor Bondsmith, you pump them full of high-caliber lead until they run out of Light to heal and then hit them until they're down again. Guerrilla warfare in the age of guns is the ideal anti-Radiant strategy.
Unfortunately, we need to cut this short because it's off topic. You're welcome to PM me and we can keep talking about this!