Like I said in my first post, the mana system needs to regenerate much faster (at a rate of about 5+wis or 10 per round or minute ooc), because this class suffers from the 5 round work day (heck, you can't even keep your seals up all day, and each time you use one, you lose 15% of your daily mana pool). Holy paladins regenerate mana in combat at a rate that is 300 times faster than out of combat, which considering the way mana normally regenerates, is completely aberrant.
As written, the only way to play this class is to only use normal melee attacks (which isn't so bad, as they are pretty strong with the retribution spec) or spam Hammer of Justice all day long because it's a great CC spell that's dirt cheap.
Also, the mana cost is pretty wonky for some abilities (Hammer of Justice is a spammable SoL that is usable up to 4 times per round and only costs 3 points per cast, while exorcism is a bad blast spell that cost 30).
As for keeping abilities at the WoW percentage, remember that some abilities are worth more in a PnP turn-based system than in a RT MMO. Stuff like letting some abilities being attack actions isn't so bad in an MMO (even instant cast melee attacks have a global cooldown, which spells with a cast time ignore), but in a PnP rpg, being able to use an ability 4 times per round (especially if it doesn't require an attack roll) is an immense advantage over being able to use an ability once per round.
As such, the effectiveness (and the resulting mana cost) need to be balanced with their actual effect in-game, not their effect in WoW.