The Birds of Prey would have revealed that a female vice-presidential candidate was, indeed, a genetically altered female canine, under the control of Prof. Milo's female daughter, Monroe Milo.
There would have been no observations of 9/11, not because heroes would have prevented it, but because two such hideous and featureless buildings would never have been drawn by a self-respecting comic book artist to begin with. Except in Central City, where no one would have noticed that they were missing.
Oracle and the Calculator would have joined forces to purge the Anti-life Equation from Google Chrome.
Aquaman -- the real one-- would have used controlled bursts of sea-water to extinguish the Chunnel fire and plugged the holes with giant tortoises until permanent repairs could be made, thus thwarting Vandal Savage's scheme to take over the world by slowing down the European economy.
Hurricane Hannah and Ike would have been redirected by Weather Wizard toward Central City, as part of a plan to rob the Sundoller at the Keystone Coffee Pier, but the potentially incredibly destructive hurricanes would have been dispersed by two miraculously non-destructive counter-tornados generated by Barry "Flash" Allen and Wally "Mid-Flash" West.
The political crisis in Zimbabwe and the Zuma trial in South Africa would have been solved, somehow, by Vixen (with secret help from the Bronze Tiger) and an improbably young and sexy black international troubleshooting U.N. diplomat who was Vixen's never-before mentioned first husband when she was modeling in, oh, let's say, Paris.
Wonder Woman would have led a parade against Sanlu Milk Company.
Wayne Enterprises would have bought Lehman Brothers Holdings, not because of its intrinsic value, but to save its employees' jobs, beating out a bid by Lexcorp, which intended to sell their body parts to scientists on Apokolips and Prof. Milo's female daughter, Monroe Milo.
S.T.A.R. Labs in Central City would have activated its new Large Hadron Collector (because where else would you put something that big?). It would, in fact, have caused an unanticipated disaster such as:
- the creation of miniature black holes, that would mostly suck in people rather than other matter, which the JLA would stop, and the people, instead of being crushed into their constituent atoms, would have been rescued by Zatanna, Vixen, and Red Arrow.
- angering a tribe of sub-atomic warriors who use miniature black hole cannons as weapons, whom the Atom would have to defeat.
- alchemical cascades that spread elemental changes through the surrounding area like a plague, which Firestorm would have to stop.
- the discovery that "dark matter" is a personified force that would then threaten to consume all bioenergy in the area, which would have been defeated by the JSA, but not before critically injuring the Ray, and, unbeknownst to his teammates, turning comic's only regularly recurring openly gay hero secretly evil. Again.
- a new color of kryptonite.
- the re-retro-re-creation of the Multiverse.