AoE has hinted at techno-organic creatures like the terraformers and the Wolves. What if the "creators" send some at Optimus? Every movie is a about Optimus with a small band of bots that represents his team. In TF5 Optimus' story could involve being stranded on a forest-type planet at the prey of techno-organic Transformers sent to bring him back after Lockdown failed. The Maximals don't have to full resemble Earth animals but, their beast forms could pay homage to classic beast modes. Lockdown mentioned how Optimus has strayed and that his creators wanted someone who would just do as he was told. What if Optimus Primal was made to be Optimus 2.0 and is a more stern leader than Optimus (similar to how he was in Beast Wars). During the film, Optimus can re-learn how to be a leader after being in hiding for 5 years as well as regain his former self and teach to the Maximals that they don't have to be pawns for the creators like Optimus, that freedom is the right of all sentient beings.