Sorry I'm late. Long day at work, that I'm still at.
I was hooked on Venture Bros. from the pilot in 2002. When they made the series, it was even better than I thought.
The first season continued on with the whole "spoofing Johnny Quest and The Hardy Boys" while introducing you to the backdrop of the world.
The majority of the second season played more with the long stemming character interactions, but also had some really fantastic episodes (I'm particularly fond of Return to the House of Mummies, Part 2).
The third season dealt more with the background of the characters and answering questions from the first 2 seasons, including how Billy Quizboy got his eyepatch and mechanical hand, where Phantom Limb actually came from, and more about the OSI, the Guild, and the original Team Venture.
My guess for Season 4 is that you will first deal with the lack of Brock dynamic for the Ventures, the lack of 24 dynamic for Monarch, and we have been told that 2 main characters will die this season. What you have to do is look at who is a success, because they show is all about failure, and any winners will surely die.