Deadline has more or less confirmed that Sylvester Stallone is out as far as "The Expendables" franchise goes. The article states that Nu Image/Millennium chief Avi Lerner had major disagreements over the film’s script, director, and “certain qualitative elements of the film” including, yes, which VFX house they were going to use for the special effects.
I'm not going to lie, I hate the "Expendables"franchise. I hated the initial 2010 film, walked out of the second film and walked out of the third film. This fourth film, which is at the center of this dispute between Lerner and Stallone, was going to give Stallone a payday of $20 million. After the third film Stallone admitted to regrets in regards to the film being rated PG-13 instead R. This might be one of the major arguments that have pulled Stallone and Lerner apart.