It's cool that a paladin can go 'all-out' in the heat of the moment and potentially screw himself later when he might need to dig deep again. Kind of like how a Spellcaster can fire everything they have at a single target to make sure they've killed them.
Also, I dug this out of the listed spell changes.
Isaac's Greater Missile Storm
Caster Level: Wizard/Sorcerer 6 (Gained at level 11/Wizard, 12/Sorcerer)
Innate Level: 6 School: Evocation
Component(s): V, S Range: Long
Save: None - Spell Resistance: Yes
Area of Effect/Target: Gargantuan
Duration: Instant
Description: A number of energy missiles (one per caster level but to a maximum of 20) appear and randomly target and hit any hostile creature in the area of effect. If there are more creatures than missiles, only the closest targets will be damaged. If there are more missiles than creatures, one of the creatures will be hit with multiple missiles. Each missile does 1d4 +1 points of damage.
• Level 11 11 missiles
• Level 12 12 missiles
• Level 13 13 missiles
• Level 14 14 missiles
• Level 15 15 missiles
• Level 16 16 missiles
• Level 17 17 missiles
• Level 18 18 missiles
• Level 19 19 missiles
• Level 20+ 20 missiles