If you don't have a Antonidas you can use Pyroblast to finish off your opponent or add a Flamestrike for AoE if you are behind.
Besides Frost Bolt and Fireball there aren't any direct damage spells in this deck so I would swap the dragons for Gnomish Inventor for card draw rather than Ogres for spell damage.
Loatheb and Enhance-o Mechano have a unique effect and are hard to replace.
Considering Gnomish Inventors are 4 dropps you can fit in some sticky minions with higher mana costs (Sludge Belcher, Sunwalker), some late game mechs with good value (stay below 7 attack -> BGH) or simply a Reckless Rocketeer for the final push.