Having TDK-level marketing for TDKR is pointless, I don't get it.
What a lot of people here seem to forget is that TDK was still a gamble, in WB's eyes.
BB came out in 2005, made nearly $400M worldwide ($205M in the US, eventually), and was regarded as a moderate success. It came 8th in the US box office that year (behind HP4, Star Wars Ep.3, WOTW, The Chronicles of Narnia, Charlie and the Chocolate Factory and Wedding Crashers - yes, I'm serious about that last one).
In the WW Box Office, BB came 9th.
The film was both Christopher Nolan and Christian Bale's biggest movie to date, and they were less bankable than the director of 'Fred Claus' / 'The Change-Up', and the stars of 'Hall Pass' and 'The Dilemma'. That's the facts that WB saw at the time.
In fact, WB did not greenlight a sequel to BB until 2006, a full YEAR after BB was released. Look at the Hunger games - after one week, a sequel was greenlit, and a production schedule was organised for a 2012 release. THAT is a BANKABLE franchise. Even after BB, Batman was not.
The purpose of the viral marketing for TDK was to promote awareness of the film, which was far better than WB expected. The truth is that WB did not expect the film to explode as it did (really, the best case scenario for TDK was double the gross of BB in the US, with a WW gross of $700M total). But thanks to a number of factors, TDK was a monster hit.
Cut to TDKR. Awareness of the film is at an all time high. Compare the amount of recent marketing to films like Avengers and Prometheus. One prologue, one trailer and one poster compared to millions of dollars of marketing for other films, and TDKR is still always mentioned.
Case in point. X-Men 3 vs X-Men 2. The OW of X-Men 3 was huge. One reason was the marketing (even though all railers showed the SAME scenes, over and over). The other reason was the excellent WOM generated by X2. For TDKR, OW is guaranteed to be big, even with little marketing, because of TDK. Theres also a good chance the film will have legs, as all of Nolans previous films have done so. There's still a risk of overconfidenece, and the film may be a stinker, but there is NO way that the film will not open big.