So I'm driving to work, trying to come up with a way to really emphasize the "robots in disguise" aspect of the Transformers concept. So what if you had transforming robots from outer space, and there's 2 factions, and they come to earth and take the form of various earth machinery. However, they're not any more durable than the alt-forms they take, which means they're not particularly hard to destroy. As such, they really have to use their alt-modes to hide in plain sight, otherwise they'll get annihilated. So the humans don't have any idea when the Transformers really showed up on earth, so literally any machine could conceivably be a Transformer. Also, there's no way for the humans to detect Transformers or to distinguish, say, a regular car from a transforming-robot-car. So your car you drove to work today might be a normal car, but tomorrow it could be a transforming robot and you wouldn't be able to tell. This would introduce a huge element of paranoia and mistrust - maybe the Decepticons aren't outright assaulting human stuff, but they're doing shady things behind the scenes... but then again, so are the Autobots. They're just as vulnerable, and initially the Autobots aren't exactly trusting the humans to a huge degree either, so the humans are just taking the Autobots at their word that they're the "good guys". So you've got robots hiding in plain sight all over the planet, taking any alt-mode they want, and the humans have no idea just how many Transformers are actually on the planet and what their intentions really are. That rusted-out old clunker sitting in the vacant lot down the street? It could totally be a Decepticon and when it gets dark and no one is looking it's going to turn into a robot and do Bad Things. What do you do? Do you recall every car on the planet, even though you've got no way to ID which cars are robots? And those robots are going to sit and wait in car-mode until you get bored and give up, because demolishing every car on the planet is unrealistic and the Transformers know that. Maybe it's all told from the perspective of the humans experiencing it, and maybe the Decepticons have been present for a while and have actually manipulated themselves into positions of power somehow, through blackmail and assassination, and the Autobots have now shown up to defeat them. I know it's a pretty radical shift from the "tone" of most Transformers fiction, and it's much more like a Tom Clancy techno-thriller (or McCarthy-era anti-communism Red Scare stuff) blended with Carpenter's 'The Thing' horror, so that'd make it pretty hard to translate into a toyline for children. Just sort of thinking "out loud" here, haha.