Hearthpwn

Leyline Manipulator is also good instead of Ghastly Conjurer.  

can i play it with only 1 cabalist tomb ? its not worth crafting since the old gods r going away in a couple of months now :/

Is this more consistent than the Archmage version?

I still don't think so. Voidwalker is a nuisance for decks like this.

By my observation, as long as the enemy has taunt/stack of armors, then this deck isn't that good compared to exodia.

Yeah, I sort of feel like if I made it to the second turn, I want to be guaranteed a win. Half the time, I want (need) to play my golems before they are a win condition. Maybe there is a way to have both win conditions. 

I've played 7 games so far, and I've lost 6.

Not sure if I'm doing something very wrong here, but I'm getting raped by aggro decks and cubelocks

I don't know which ranks are you playing on, but aggro was always a hard matchup for defensive types of mages. I would recommend you playing some other, faster decks till you hit rank 5 (Luzkan Aggro Mage may be a good one). At higher ranks there's more control decks, therefore your chances of winning are higher. Against warlocks your most important cards are Frost Lich Jaina, Dragon's Fury and Blizzard / Frost Nova combined with Doomsayer. There's no way you can kill Warlocks with Arcane Giants Quest Alex combo because of Voidlords, so you got to outfatigue them with your Water Elementals and keep a way to deal with Warlock DK (as I said - Dragon's Fury, Freezes + Doomsayers, although your opponent is most likely to deal with doomsayers by using Siphon Soul, so be careful with them).

Dragon's Fury replacement? I think it's better to get the 7 mana 4 damage to all enemy minion or Volcanic Potion instead, for a better consistency. I also feel like ghastly conjurer can be replaced.

Sen'jin Shieldmasta

Ghastly Conjurer's purpose really isn't to get you a taunt creature, but rather to help finish off the quest if you're one or two cards behind and then the two taunt creatures help buy you another turn to get it all together. I've won several games just because conjurer did exactly that when otherwise my opponent had me dead to rights. YMMV though.

I have replaced Zola the Gorgon with the Molten Reflection, cause I don't have it. Is that better than Molten Giant? Thanks.

Similacrum seems to get the same job done for 1 less mana.

Zola is used to avoid the usage of another low mana spell, so dragons fury gets more value.