I see it like this...
If they decided to make a movie about the original DMC series, it would just be an action flick. A cool one, but there would probably not be any depth to it and it would most likely end up in the pile of videogame movies gone wrong. Personally, I have a weakness for such cheesy videogame movies, such as Mortal Kombat, Street Fighter, The Super Mario Bros, Prince of Persia (which in my opinion was phenomenal)... but those movies are more like cult classics than big blockbusters, so it is understandable if they won't touch it.
Also, they would probably screw something up and make tons of fans angry... Because, you know, videogame fans are so ungrateful and prude when it comes to their beloved games.
If making a movie about DmC, well, then they don't have to think about all the angry fans, because they are already angry because of the DmC game. If anything, the movie could turn into a hit and maybe turn over some of those angry fans. And if not, then it's not that big a deal except for some money lost on a failed project.
As for the Twilight reject... read my sig.