Here is my issue with spell failure. The paladin has been faithful and a good servant to his god. He needs that spell to save his or someone else life or to complete an important mission. So why does his god choose that moment to be a dick?
The story teller in me just screams in agony over this.![]()
This is a good point; and I'm glad I waited until morning to reply. (You're right, "story teller" makes much more sense.)
So if I read you right, you're equating spellcasting with implement use and the pre-4e trappings of verbal and somatic components?
In that case, a paladin who can channel holy power through his sword to smite his enemies is okay, but one who calls out to his deity to bless his weapon at the start of a fight is not?
What about at-will prayers that enhance his fighting ability (say, granting a bonus to attack rolls or damage rolls or AC)? What if they were mechanically similar to Essentials fighter stances in that the paladin only has to pray once (with a minor action) and he continues to enjoy the benefit until he "switches" blessings with another prayer (and another minor action)?
How would you distinguish between a lay on hands ability that can be used once per day and a cure X wounds spell? Would it be on the basis that one requires a verbal prayer, somatic gestures and a holy symbol, and the other does not?
Using a deity as a Vancian spellbook just feels very undivine to me.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.