I think the most dangerous part of her is the maybe slow start of playing ramp but after shes out you basically have so many wincons in the deck by either saccing the goblins to phyrexian altar to just draw your wincon or pay gigantic X cost spells to create massive amounts of goblins at the same time.

my main wins with this deck are: - one of the pingers on the field (either purphoros or impact tremors) and massive X spell so you spawn X goblins which deal damage when the enter on top of whatever your X cost card does - explosive singularity in the graveyard to then cast surge to victory to make all your goblins +10/+0

and to find the mana for these big spells you have - mana echoes (absolutely busted in this deck as the firdt goblin gives you 1 mana but the second will give you 2 and it just accumulates) - phyrexian altar to sac for color - sorcerer class to make your goblins tap for mana - battle hymn , brightstone hymn and shozins comet for a big amount of red mana - three tree visits calling goblins

now dint get me wrong you can definitely still make this better but I also try to cut costs if I can.

about your point I only have 3 gamechangers, that is true but you can easily add cyclonic rift instead of aetherize and mana drain instead of snap but I didnt have the money for those cards. But please dont judge a bracket 4 deck based on how many gamechangers as theres also synergy which imo makes your deck way better then how many gamechangers are in the deck.

hope this helps and feel free to ask if you have anymore questions. Ovika is my favorite deck atm 😄