A Voltron commander can become so threatening that opponents have to cast an Austere Command to blow up what's attached to it or a Damnation to destroy all creatures and temporarily level the playing field, or risk dying in combat
This is going to change things
All the paradigm spells are inherently card advantage, since they're single cards that grant you extra cards on each subsequent turn
It is very possible to cast a Brainstorm, stack three massive Creatures on top of your deck, and then cast Koma, Cosmos Serpent and cascade into three threats on top of Koma
Now, my problem with [casthaven]Furance of Rath[/casthaven] effects is that I really only ever see them seeing play in one of two different style decks: either hyper-aggro/commander damage decks that use them as overruns, or in damage combo decks that use these doublers with cards like [casthaven]Stuffy Doll[/casthaven], [casthaven]Mogg Maniac[/casthaven], or [casthaven]Repercussion[/casthaven] to quadruple spells like [casthaven]Blasphemous Act[/casthaven] for a fairly instant combo kill
2 Nashi, Moon's Legacy The past is present with this Rat Shaman One of the best new Rat commanders to come out of the Phyrexian Invasion block is Nashi, Moon's Legacy