Hi mega,
first of all, I have no access to premiums, so I can't test it.
the observation I have is that you may have called it a goblin deck,
but in fact it is an aggro deck that happens to contain many goblin, and the only tribal reference is rabblemaster's goblin must attack each turn, and that his attack gets boosted by every other attacking goblin. so with so many instants and sorceried in your build, I would consider using
kiln fiend, look how cool he is.
I've thought about Kiln Field, but I don't care for him in this build. While the 2 Rabblemaster's are the only things that are really related to the goblin tribal synergy, there aren't any goblin cards I want to take out for Kiln Fiends. Bushwackers, Shortcutters, and Rabblemasters all impact the board and help push damage through on the turn they're played. Kiln Fiend doesn't do anything the turn he's played except act as a removal magnet (ok, Rabblemaster is a removal magnet too). So that leaves me with removing some of the non-creatures to make room for Kiln Fiends, and I don't really like those options either. Trumpet Blast won't stop him from being blocked. Shortcutter can stop a blocker, but that doesn't activate Kiln Fiend's effect. Coordinated Assult helps him survive combat, but that's still not getting that extra damage through. Skullcrack is best used in response to lifegain and is usually one of the last cards I'll play. Shock has good synergy with it, except I don't like using early shocks to remove blockers, I like to hang onto them as the last cards in my hand in case I need to throw them at my opponent's face. I'd rather play shortcutter before playing shock to stop blockers, as the shortcutter goes better with a Trumpet Blast or Bushwacker as a follow up.
So yeah, I don't really have a spot for Kiln Fiend in here.