Brand Ult Rework

Brand, like many old mages, is combo heavy. Brand especially. Currently his ult will just jump to a target with his passive already applied but that's not really that cool IMO. It's more like a stronger Fiddle E, I heard someone say this and it got me thinking. What would fit a fire mage who specializes in Nuking single/multiple targets for an ultimate?

A giant AoE Fireball. But here me out.

Brand Channels for 1sec before dropping a giant fireball onto an area. The size of the Area will be about as big as Trundle's W. The Cast Range can be about Brand's W. (I'm not good with the ranges and numbers so that can be subject to change.) It'll do a large amount of AoE damage to his opponents. However the part that brings it home is that it will apply the passive of all of his other abilities to his opponents.

Examples: If two enemies have blaze and the other three don't. The two with blaze will take bonus damage and be stunned (Like his Q and W together). While the other three will have blaze shot too them (Like his E).

This makes Brand players try to set up the ult even more than before because of the big damage possibilities. If none of them of them have Blaze it's just an AoE nuke. However if you hit someone with your W prior, the ult now isolates that target and nukes them harder while still hurting the rest of them. It's value will come from comboing with the rest of his abilities. Tell me what you guys think. I'm somewhat fond of Brand and I feel like this could make an interesting improvement to him.