Dunno why there is Hammer of the Naaru in Big and Control Paladin.. You have the new weapon and the new hero card (that weapon never breaks) yeah sure there are cards which can destroy your opponents weapon but you shouldn’t count them into your deck.
And why is Cariel hero card not in the hand buff Paladin? The hero power is perfect for this archetype

No.
A a 4 Mana 3/3 you can play with coin on turn 3 and play another 2 minions, weapons or spells for 3 Mana.
So you could play cards on turn 3 worth 10 mana. That’s not weak at all if you can play him on curve.

I think you misread the effect.
It summons a beast that costs one less than the beast that attacks.
At least I read it that way.
F. E. a 5 Mana beast attacks, then you will summon a 4 Mana beast from your deck.