It's led to the recent trend of stapling the effect you actually want onto a creature with appropriate-stats-for-effect-level. Crucible of Worlds is a 3 mana effect. As a creature, it should be green. It should therefore cost 2G. A 2G creature is reasonable at 2/3. Therefore, Ramunap Excavator is appropriate.

My modern deck plays entirely creatures, and entirely humans. It has duress, thorn of amethyst, nevermore, and into the roil main, with the option of getting disenchant, rule of law, and electroylze out of the side... as humans. It's effectively made spells obsolete, since the spell you want is probably a creature now.