Half-Blood prince is going to be the sixth Potter movie. So it’s no surprise that by now they have a marketing formula they think works and is not worth straying from. For the posters this means lots of character posters showing the characters either looking distressed or looking ready to fight back. Apparently it also means a blue tinge. And every once in a while it means a tagline that says very little about the story but makes the whole thing sound big and scary.
Complaining about this is like complaining that a Big Mac still tastes the same as ever. While it works they won’t change it, at least no meaningfully. And for many of the fans the familiarity is a big part of the appeal.