This is the kind of role, that if handled by an actor with serious chops (and lets face it, I think about %50 of that is going to be having a good director) it could be a career making role with an oscar award attached.
While I like Kutcher as a person, respect his support for startups, I also recognize he's more of a social media celebrity, whose got comedic timing, but hasn't yet shown (or maybe had the opportunity to show) significant dramatic chops. Its quite possible he's got them, and he's suffered from being type cast. (Remember how Demi broke the mold by playing GI Jane... but then that also seemed to end her career.)
Sometimes unexpected actors can do great-- Tom Cruise in Born on the Fourth of July was a surprise to me, but I credit Oliver Stone for that one. The other example I can think of is Woody Harrelson in Natural Born Killers.
Harrelson's previous career was on TV as the good guy midwesterner kid, but Oliver Stone said "I saw something evil in his eyes."
I really don't think of Ashton Kutcher as having the necessary chops for this role (and the source material is itself so half assed and shallow that the project is starting from behind already.) This runs a very real risk of being of TV Movie-of-the-week quality.
I hope they get a great director and some serious work on the script, and that Kutcher dedicates himself to the role.
I'd love to see a biopic of Steve Jobs as on the nose as Val Kilmer's portrayal of Jim Morrison in The Doors. (Which is another Oliver Stone movie, but I promise you I'm not obsessed with Oliver Stone, he just handles this kind of material really well.)
Edit- I missed the part that this isn't based on Isaacson's work. So, whether the source material will be week (like almost everything written about Jobs since he didn't give people a lot of access) or not is open to question.
Also, as dlf notes, Kutcher was in The Guardian where he played a dramatic role, and did a damn fine job. I'd forgotten about that movie... But that convinces me that Kutcher has the potential to do a brilliant Jobs performance. Lets just how the script is good and the director is strong.