Sorry if this has been posted before but I didn't see a thread on it. Just seen this on Ronnie's Twitter.
Looks like you will be able to really get in depth with the RPG element in MyCareer and and have conversations with your agent while forming your players personality.
From what I have seen this mode is really cool and something very unique and will make MyCareer much more than just playing exhibition games, basically we really get to "live the life" which if I am correct is something we have been asking 2K for since 2K10 MyPlayer.