It didn't take long. With RoE came Wall of Omens, a huge asset for UW control in the Jund matchup, which went from being slightly favorable to comfortable. Gideon Jura's utility against creature-heavy decks of any type simultaneously added a solid kill condition to the UW arsenal. Bant was propelled into top-tier status with the addition of Eldrazi Conscription, which, in combination with Sovereigns of Lost Alara, has been populating top eights for several weeks. The absurdity of Emrakul, the Aeons Torn means that if Polymorph resolves, the clock only has to tick twice. See Beyond is a great aid in finding that game-breaking Polymorph quickly as well as putting a stray Emrakul that finds its way into a player's hand back into his library. Consequently, the deck type of the signature card's name is no longer the rare sighting it once was but has instead become a tournament regular.
Where the colors stand post-RoE:
Lands are categorized based on the mana they produce (or in the case of fetch lands, the mana sources they are able to indirectly produce). Gold cards are assigned fractionally by their colors (Putrid Leech is .5 black, .5 green; Rhox War Monk is .33 white, .33. green, .33 blue, etc). Eight of the top 100 are colorless; consequently the percentages do not add up to 100.
These additions have put blue back in contention for the top spot, even though most of what RoE added to make blue viable once again isn't even blue. Despite comprising more than a fifth of the metagame, blue remains the only color that simply cannot function without a heavy dose of something else (usually white).
Blue's resurrection has come at black's expense. Vampires has dropped off the competitive circuit, as it has little ability to deal with combo decks like mythic conscription and time sieve and is impotent against planeswalker-heavy builds like American gladiators and UW control with Jace, Elspeth, and Gideon (Vampire Hexmage can only be stretched so far). Further, the mortal blow Kor Firewalker delivered to red deck wins has eased some of the pressure on jund, and jund continues to absolutely wreck vampires.