Questions about a balanced staff build
I would suggest approach 20/0/0/20/20. It will better server Lightning Hammer skills with the power and condition duration, to make the burn last longer that you apply right before going hammer for example. Rather than the condition damage and toughness.
You can get the condition removal from water and keep attunument swapping while in lightning hammer for the extra boons from Elemental Attuning. Or decide to stick in fire with 10% extra dmg trait while with lightning hammer.
You should probably pick up Mist Form utility to survive hairy situations. And arcane wave for second to get familiar with using combo field use as much as possible.
But there are many ways to do it, quite near equally as potent for pve purposes.
Arcane Power is extra good with lightning hammer AoE, as you will get 5 swings with guaranteed crits. Aka 4×3 + 5 crits, instead of just 5 like with normal skills.