A couple thoughts:
1) I think this feat would work in a world that is bristling with magic. So it's not something I'd allow in my own game. I feel that it takes away the importance and roles of druids and clerics in the world. Also, when it comes to divine magic, aren't the PCs asking for these boons? Why would Pelor give Random Farmer access to magic? And in some cases, especially paladins, these casters are chosen not trained. What happens if I need to atone? What about alignment steps? Do I need to match that deity's? Be within one step?
2) What is your caster level for these spells? Is it first? Then why would I ever spend a feat on this? If it equals your HD, then it's ripe for abuse. Lets ignore CLW as a source of emergency healing. But you've got spells like Divine Favor, Longstrider, Goodberry, Shield of Faith, Entangle, and the summons.
3) There are some similar feats in Complete Arcane. But they only give you three cantrips as SLAs that work 1/day. I would create something closer to those rather than letting the player pick their own spells.
4) What is the DC of the concentration checks?
5) Okay, this is nitpicking but what if I pick my class to be something like Disciple of Thrym?