Just a stray thought here.
Hasted, rapid shot, divine power, 7th level cleric... 14 dex... does all of that stack? I'm not positive, but I guess so. Assumed undead target with a touch AC of 11 for now.
+6/+6/+6/+1 ranged touch, 1d6+5 each. Assuming 75% hit on +6, 50% hit on +1, Average damage 38.25 damage on a round.
Searing light +8 (85%) for 7d6 against undead. Average damage 20.825 per round.
If the spell is also a swift action, the first bit can be repeated. The cleric fires his volley this round, keeps 3 charges for next round. Next round, he fires 3, then as a swift action casts again, and fires 1 more (since you can use a swift action in between attacks). Then the next round he does 4. etc. Also, against a slightly higher AC the mutliple attacks lose slightly more damage I believe. Oh, and of course point blank shot could increase the damage in some random cases.
It's not anything too rediculous (since you are throwing a 4th level spell, a feat, and a buff coming from a wizard, bard, or potion), but I'm just stressing one of my concerns if you want it to be a 2nd level cleric swift action spell.