Its just ludicrously efficient for its cost, combining a meaningfully disruptive ability with a stout body and a miserable ward cost
Decks do need building with Stoneforge in mind but not to the extent of cards like Goblin Welder or even Land Tax
The Myriad Pools can offer some mana ramp and utility, but you need a lot of permanents in your deck for this to flip
Instead, a second "reflexive" ability triggers whenever you activate that ability
Ankh of Mishra Mishra Mishra's Bauble Mishra's Command Mishra's Domination Mishra's Factory Mishra's Foundry Mishra's Groundbreaker Mishra's Helix Mishra's Juggernaut Mishra's Onslaught Mishra's Research Desk Mishra's Self-Replicator Mishra's War Machine Mishra's Workshop Mishra, Artificer Prodigy Mishra, Claimed by Gix Mishra, Eminent One Mishra, Excavation Prodigy Mishra, Lost to Phyrexia Mishra, Tamer of Mak Fawa