Hearthpwn

Why Grumble with jades? You'll summon jades and pull it all back after?

This deck was not build around Shudderwock. It uses battlecries and jades while controlling the board with good spells. It's still a good deck without Shudderwock. Most of the matches I won, I didn't even use him. Grumble is situational card, as I wrote in description you can replace him. I mostly use him to repeat battlecries for 1 mana. Or use him to recover the damaged minions and make them full health. So you should use him efficient and smart. Not like most people use it for repeating awful otk.

Loatheb is a MUST.

When you play Shudder prob build a board with 8/8 and 9/9 or poweful jades. With a +5 cost in opponent spell is gg

I agree with you, Loatheb is very good card and has good synergy with Shudderwock. As I explained in description, you can replace it with Grumble. 

Nice deck ! Never thought about Rummaging Kobold in jade shaman, which is actually a very good idea. Is bloodlust really necessary?

Rummaging Kobold is good indeed, you can even use it with Murmuring Elemental to get 2 weapons or keep the elemental and use it with returned weapon and have 2 jades, depends on the situation. Also you will benefit kobold effect with Shudderwock.

Bloodlust is not necessary but it's a nice card that you would like to have in your deck.

At first, I didn't have it in the deck, in some matches I wished I had a bloodlust with me. Then I tried it in some matches and it worked better than I imagined. Now it has permanent spot.

A tip: Don't use it just for finishing purposes, use it efficient. And I believe you will encounter moments to use it that way.