They can sweep the board with 4 mana on the board. UR can sweep with 3 mana.
They can put a creature on topdeck for 2 mana. UR can kill it instead... and Scry 2.
You know, that's the difference.
Have you read Sphinx's Revelation? Izzet Control doesn't have a single card in any list that says "red can't win anymore" Aetherling doesn't do it, Chimera doesn't do it, opportunity doesn't do it. Also, Azorius Charm is one of the best removal spells in standard it hits everything but BBoV and Dragon. Sure they draw it again next turn but it's still a 1-1 trade that lets UW survive a turn and the longer the game goes so does the chances UW wins. UR may be better than UW against weenie aggro, and I'm not convinced it is, but I believe the matchup against aggro is better than 60-40. The only reason U/W didn't win in Worcester is because he was mana screwed two games in a
row with a 2 color deck w/ a solid mana base and card draw. You can't just count on that to happen to win.
Mono Green has no way to play around wraths. They don't have the tempo. They have big dumb creatures that fold to UW.
GW is too greedy in terms of manabase to be playable. I was one of the very few advocates of GW here, but got proved that it's not gonna be a deck for a while.
GR... it actually lacks of good targets to ramp into. The best thing you can ramp into is probably Green Garruk. He's THE shit on the block. On the other hand, creatures just don't feel powerfull at all. There are no Titans or Avenger of Zendikar - we're talking about Stormbreath Dragon and Kalonian Hydra. Both have their issues, vulnerabilities and don't provide enough of value when ETB to be worth ramping into.
There's also Ruric Thar, but he severly limits your deckbuilding.
You play around wraths by not committing. It's easier to do with green because Architect doesn't hit
your creatures as hard because you aren't swinging with a bunch of 2/x's you're swinging with 3/x's and 4/x's.
I disagree that GW is too greedy, I think the build may not be obvious but it will be a player, the cards it has are just too strong.
GR doesn't have to be ramp. You can just take mono red, add in some stomping grounds and overgrown tombs and GCR people all day. Maybe mix in a couple Domri and some other fat (Poluk is good) and you're already an aggressive deck that has a better mu against other red weenie decks.
GB may be a thing again. Desecration Demon is still a card, I'm not hopeful about that though.
The meta will shift. The better RDW gets the more likely you are going to run into slightly larger aggro decks that pray on RDW. Then midrange decks that prey on the slightly larger aggro decks, then RDW will go under the midrange. All the while control decks will be adapting their answers as the meta shifts. During this cycle UR will only be good as long as it can reliably
kill the other creatures. UR can't even kill Ember Swallower without Turn//Burn or 2-1ing itself.