When Pyromancer's Goggles was seeing play at the beginning of Shadows over Innistrad Standard, many players adapted the U/R lists into R/W variants that eschewed Jace, Vryn's Prodigy and Thing in the Ice for Nahiri, the Harbinger. The idea was to be less aggressive, blank your opponents' removal spells, and use your removal spells to keep the battlefield clear while generating advantages with a powerful planeswalker.
This list appears to be a similar adaptation made to the current U/R Thermo-Alchemist deck that has risen in popularity since Pedro Carvalho's impressive performance at #PTEMN. The strange thing is this deck premiered on the same weekend as the Pro Tour, so this time the “adaptation” is a bit ahead of schedule.
The list is certainly more controlling, even eschewing Thermo-Alchemist for Weaver of Lightning to mow down small creatures or upgrade your burn spells to handle larger ones. The other creatures, Goblin Dark-Dwellers, and Bedlam Reveler provide some card advantage alongside the pair of planeswalkers.
But even though this list is slower, it can still apply plenty of pressure between its large creatures, burn spells, and Chandra, Flamecaller. Therefore, I don't see the average kill for this deck being that much slower than the U/R version. If you are forced to use your burn on creatures and the game goes long, you have Secure the Wastes and Needle Spires to deal damage in bunches while both players are depleted on resources.
The sideboard lets you shift to a more aggressive gameplan with the powerful Hanweir Garrison alongside Hangarback Walker and Pia and Kiran Nalaar. When your opponent brings out their cheap removal spells because they were ineffective in Game 1, Hanweir Garrison is the perfect card to punish them, snowballing completely out of control in only two turns.
The aggressive elements in the sideboard are complemented by some bigger threats, notably Linvala, the Preserver to give you a game-breaking creature to tutor for with Nahiri, the Harbinger's ultimate. Furthermore, the threat of Linvala will cause your aggro opponents to rethink ignoring Nahiri, which further muddles their attacks and buys you more time.
Fevered Visions is the most significant loss in moving from blue to white, especially in a metagame infested with big mana decks. However, as we saw last weekend, Standard is shifting toward more aggressive decks with the rise of U/R Thermo-Alchemist and the adaptation of Bant Company against the Pro Tour metagame. This more aggressive metagame is certainly better for R/W, making this deck even more ahead of its time.