This *could* be an interesting choice for him. But a lot of the factors of the success of this film are outside of his control (the script, the director, yada yada yada). He's clearly opting to play a role that's outside of the "good boy" character he's been playing. From what I've read so far, they're setting him up to be the "villan" in this film (I use that term loosely, of course). I can't wait to see what he does with a character that has less-than-noble intentions. There are a lot of ways the writer (s) could take this story, so I look forward to seeing which direction they ultimately decide to take.
I would love to see him in a thriller. He needs to get on that ASAP.
tofu

so zac playing the antagonist!
that will be a change

Well, the way they're setting it up, he is. I like this...it's a good change for him. I'd be curious to know how they're going to take this...there are a million ways to tell a story, so they could end up becoming friends in the end. Who knows?
tofu

lol yeah! that would be a cool twist
from enimies to friends!
Hehehe...right? I just want to see Zac get angry and knock something down.
tofu
He needs to vary his filmography to show people in the industry and viewers what he can do,and he is doing this now by picking a variety of different roles.

About the director:
"In Hollywood, studios must prepare to strike while the iron is hot on a film to film basis. In a world of “what have you done for me lately?” they don’t come into the game any hotter than director Nicholas Stoller.
"In 2008 Nicholas Stoller jumped on the scene with the side splitting comedy Forgetting Sarah Marshall, which starred Jason Segel and the lovely Mila Kunis. Stoller proved to have a keen eye for the comedic genre as he went on to direct the two highly praised films Get Him to the Greek and The Five-Year Engagement .
"As Efron continues to shed the “good guy” image of his High School Musical days, one has to wonder how he will hold up against the often raunchy Rogen – of course that might be the comedy hook this round. Assuming negotiations hold up and Stoller takes the job, it can’t hurt for Efron to be taking direction from a director who knows a thing or two about comedy."