So here are some TF character designs I've been thinking of, based off of faction symbols. (In all cases, the head is the faction symbol)
The autobot is large and bulky, with big square shoulders, and a very squared off atheistic, with a lot of strait lines and flat surfaces, and also a good amount of chunk.
For the decepticon design, he's about the same size, but has a lot more jagged edges and sharp points, along with large pointed shoulders.
Maximal has a very sleek and fit design, with smooth edges, organic shapes, and a bit of a wolf motif, maybe even with clawed hands. Also red.
Predacon has a very insectoid design, with three fingered hands, and little sub arms like Animated Waspinator, and digitigrade legs.
Both Maximal and Predacon are a bit smaller than Autobot and Decepticon.