Best of all, it's much tougher to counter Mount Doom's ability than it is to counter board wipe spells like Damnation or Blasphemous Act
As a two-ink cost card, Morph, Space Goo, is an incredibly cheap way of getting some nasty cards onto the table very quickly - thereby putting your opponent on the back foot very early on
The problem I see here is that none - or maybe few - of these want to really be in a deck together
A common rule of thumb is to run at least 45 inkable cards out of 60 so you are not stuck unable to ramp
Saheeli, Filigree Master You can +1 her to scry 1 and then tap an artifact you control and draw a card, so scry into card draw is quite nice
At four mana, he can sit at the top of your mana curve, and if you manage to drop a haste enabler such as Goblin Warchief, you can start doubling your goblins straight away (which then also have haste to attack the turn they enter)