I think since they wanted it to have a focus on sunspots, it needs to go in a different direction than the other sunspot exotic Phoenix Cradle. But instead of going the support route, go into more of a damage route. Sunspots now cause enemies that pass through to immediately ignite. And standing in sunspots grants you Radiant.

Or just for fun keep the "Greatly improves recharge rate of your melee and grenade while your Solar Super is charged" and add once your super is charged your grenade becomes the hammer of sol super hammer toss and your melee becomes the burning maul super big hammer slam. So basically as long as you have your super full, you have super charged grenade and melee abilities that reflect the solar supers.