Can't say how reliable this is (it's from facebook) but it doesn't seem that far of a stretch at all.
Certainly could be real. But the changes seem so small and nonsensical I'm going to vote fake. Time will tell. EDIT: Actually I'm pretty sure fake- the old arm guards from previous movies (that he didn't really have in AOE) have reappeared. Still, we'll see.
After some searching, it's fan-made by Lászlo Vén. Transformers 5 - Bumblebee Full Concept Art (Fan-Made) - YouTube
It's clearly fan art. He has the crown straight from Optimus and his feet are from the previous trilogy.
Bumblebee should not become a Prime! Even if he leads the Autobots they should just keep him the way he is. After all it's your decisions and actions that make you a good leader, not the title. Bumblebee lacks experience to become the ultimate Autobot leader, but he should not have problems leading a small group like the dirty foursome.