Sorc advancement, but with both Arc and Divine. Not bad.
It's like a Wisdom Sorceror multiclassing Divine something, for free.
Up to 15th level ... the Turn ability looks OK.
And then nothing really. Sort of a hacked off caster.
Iot7FV always works as a PrC.
ArchMage from PHB can get some strange, but good interactions going.
Persisted Divine Power and also a persisted arcane something, is a unique combo.
Maybe turn into a Gish above 15th level.
Spellcraft DCs can be cranked up with custom items of spellcraft. Easy enough.
the Sense Magic (ex) thingy, is completely outside of normal D&D stuff. Good luck.
If there are items, or feats, or even Aid Another checks ; well that looks to me like the hinge of the class.
Trying to figure out spells, in the middle of combat, is a waste of actions.
Out of combat, you go to a town, and you swap spells you know, for spells you don't.
Basically free expansion of your spells known.
Loading spells before combat is an obvious tactic.
If the metamagic inner workings, cause the Sorc style full round to cast thingy,
then loading a metamagic'd spell before combat, and then casting it later in combat,
SHOULD be a less than full round casting.
But I don't know the game or the mechanics.
If it's OK, that's another interesting spot.