A New Kind of Feat for 4e?

I had a flash of inspiration the other day that might turn into a whole new class of feats for D&D 4e - power source feats. Rather than being tied to a single race or class, these would be tied to power source. That way multiple classes, including some not yet created, would qualify. I don't think anything quite like this currently exists in either Player's Handbook.

The specific genesis of this particular feat was some general worrying about how effective Kain's Cadre will be against the impending zombie apocalypse (see last paragraph of that link). I was trying to think of ways to amp up the dragonborn cleric so he could really shine against the undead (as a cleric should). I figured one simple way that probably wouldn't break the game would be to somehow add the radiant keyword to his breath weapon. The best way to do that seemed to be with a feat.

Since I was adding something to a breath weapon, dragonborn would be a prerequisite. I thought about making the cleric class a prerequisite but that seemed really restrictive (except to the single character I intended this for, in which case it's not a restriction at all). On the other hand, it didn't seem like a feat the dragonborn rogue should qualify for. Thus, the idea of adding "divine power source" as a prerequisite:

Radiant Breath

Prerequisite: 11th level, dragonborn, divine power source
Benefit: You add the radiant keyword to your breath weapon.

Posted for review and comment. Great idea? Terrible idea? Want to see more? Didn't want to see this one? This feat should be heroic tier? This feat should be epic tier?