Over at Football Study Hall I explain the philosophy of offenses using unbalanced sets, fullbacks, tight ends, and multiple RB formations to try and confuse opponents before running them over.
The main idea with this style of offense is to use a variety of formations, sweeps, and multiple ball carriers to obscure the fact that the offense is ultimately just blocking a few base run schemes and to provide easy constraints for the offense to punish the defense with. Rather than using the option, the spread, or the passing game to protect the base runs the offense uses confusion.