As someone who has been following & predicting the box office every week since 2004 (and on & off since 1999), I have a decent eye for how films will do. I am not the most consistent week to week predictor (there are others on the web much, much better than I), but I have developed an eye for break out hits and under performers.
In my time following it, I am hard pressed to find a film which is quite as marketable as MOS seems to be (especially considering that MOS isn't a sequel. For sequels, the biggest piece of marketing is always the preceding film). Pearl Harbor in 2001, Spider-man in 2002, The Matrix Reloaded in 2003, Star Wars - Episode 3 in 2005, King Kong in 2005, Pirates of the Caribbean 2 in 2006, Transformers in 2007, and so on were all up there. On paper, it is tough to find a better film.
The brand 'superman'. Mega action, serious drama, serious romance, I assume some comedy. It's light and bright/not dark and gloomy. Zack Snyder is known for his money shots, and this is the mother of all actiones. It is Star Wars meets Spider-man. It appeals strongly to men and women, children and the elderly. Amy Adams is a popular actress, Russell Crowe, Kevin Costner, and Diane Lane very famous names. Henry Cavill's face - saying this straight - is the show stopping type of a Pattinson or younger Brad Pitt.
From an individual films perspective, I can't think of any for whome it would have been easier to give it the highly coveted "serious mass appeal". This should have the interested from the teenage and young adult crowd that the Nolan films had, while having the interest from the kids crowd which Raimi's Spider-mans had. This should have more interest in the romance crowd than any superhero film has ever had. This should have interest in older generations (for whome Superman was a more popular character) than any other super hero.
Theres no excuse for this opening below 100m. A full kick ass trailer with the NCAA championship can solidify MOS as the summers big break out movie (Trek and IM3 are more expected to be huge).