Producer Lorenzo di Bonaventura explains :
“We were headed down the Bumblebee path well before the release of the last Transformers. We had felt that with the fifth movie, we had sort of run out of room with where to take it. We’ve gotten a lot of feedback from the fans that they wanted us to do a deep dive on one or two of the robots, because they wanted to get to know them better.”
He also confirms an Optimus Prime movie was discussed at one point, and di Bonaventura went on to explain why they chose to go with their yellow comic relief character first for the standalone:
“Bumblebee was selected because he’s such a loved figure, and he’s also more emotional than Optimus. Those were the two likely characters. [Optimus] is a stoic leader, and you can count on him. Whereas Bumblebee is the one who is more emotionally volatile. He has a lot of ups and downs. So it seemed like the best character to try for the first time zeroing in on one Autobot.
Still, if Bumblebee turns out to be something fans enjoy, then Optimus Prime is the next best candidate for a spin-off. I’d certainly like to do that. It would be a very different kind of movie than a Bumblebee movie, but equally interesting and different. If Bee’s successful, we can have a Bee 2, no doubt.”
“Bumblebee” is set to hit cinemas on December 21st.