The best way to get this working well is to remember your curve and gameplan- without the stabilisation tools that most other tribes enjoy, goblins will usually try and race the opponent, finishing out with grenade and lightning bolt. Its tried, tested, and enough cards have been printed to support that plan that it runs smoothly.

Running matsterwork into Thud as extra goblin grenades is a strong option- no problems with that- it just needs a stronger creature plan to support it.

You really only have 4 1-drops maindeck (the firebrands) so turn 1 plays will be awkward- wardriver and fodder are decent 2 drops, but most of your creatures start the 'go wide' plan in the 3-5 drops slots, and only have haste by virtue of Goblin Warchief. This is gonna be awkward, because this is usually the point where the board gets reset by a Damnation or Sweltering Suns. You should look at masterwork into thud as a 4 drop too, as it really needs your creatures on the board to function.

Boggart Shenanigans is a cute card, but its usually a worse Impact Tremors. It does have its place (hello there Skirk Prospector/Enduring Renewal) but only playable as a redundant combo piece.

I'd look at doing the traditional goblin thing and dropping your curve, focussing in on Foundry Street Denizen, Mogg War Marshal, Goblin Instigator into Goblin Chieftain. This will give you a lot more early game damage, and help immensely with consistancy.

Thanks for the advice, I recognize I need more cheap goblins and ways to produce tokens, and as you say the first 2 turns are difficult right now. Foundry Street Denizen would be a nice addition and I already have a set of Goblin Instigator. I'll take what you said in consideration and work on the mana curve.

I was trying something different but it doesn't work as expected to be honest, mainly because I fail to produce enough goblins in the first turns.

If I can fix that, I'll definitely add Goblin Piledriver to the main, but I agree on Goblin Chieftain, giving haste to these goblins is so good I can't rely on Goblin Warchief to do it by himself.

Boggart Shenanigans is useful but not enough to keep 4 of them, I might bring it down to 2 copies.

Thanks again !