Human characters in Transformers aren't boring. We just need the media to stop slotting them as Audience POV type characters, stop weakening their potential to have their own meaning instead of 'accepting meaning' from the giant robots. These characters also dilute the cast, because they don't have much of their own point to make. I don't think they improve audience ability to empathize at all-- they demonstrate lack of trust in the audience.
Some of the Transformers human characters I like most:
G1 had to be 'sincere' because it's not derivative material yet. The 'style' is dated, but it actually has a lot of great humans. Sparkplug and Spike's working-class background feels like a natural fellowship with the Autobots, I like Carly's attitude to shoot high and graduate MIT when science & technology are main ideas, Chip in a wheelchair is relevant to ideas of 'mobility' when many other characters also use wheeled mobility.
Sari from TFA is a pretty good human character because she has a direct relevance to the idea of a robot being 'in disguise', when the main characters largely weren't in that series.
The TFP kids are a little lukewarm but I did enjoy Miko's implicit question about the Realness of Robot Conflicts: like toy fights, or like wrestling, or if they have actual, mortal consequences.
I did like the emphasis on Earth in Earthspark, but I sort of wish Dot and Alex (who inhabit two meaningful archetypes to Transformers, 'The Soldier' and 'The Fanboy'!) didn't have human kids. There were weird discrepancies between raising human and robot kids that soured over time, and Robby and Mo wouldn't need the Empathy Sleeve things if there were more organic reasons for them to be involved. I'm not sure they actually gave young audiences a POV when there were so many 'young' robot toys to sell POVs offered anyway?
Here is my list of human character concepts I think would be good in a Transformers series, just for who they are and what that puts on the table:
The Soldier, but they are not proud and are aware of ways the military manipulated them into seeing others as 'the enemy,' Transformers included.
The Car Dealership Salesperson, for whom most vehicles are consumer products intended to be sold as property.
The Horse Girl, when every part of her hobby is influenced by how a cavalry used to be one of the world's most important military technologies-- whether she likes it or not.
The War Thunder Forums Regular, quick to point out that the forms adopted by some Transformers have also been outmoded by really modern military technology.
The Homeless Person, for exactly the reasons you understand.
The Gangster, who has been an outlaw before, been to prison before, and knows criminality in ways besides 'that's bad!'
The Sex Worker, who can speak on how 'what their body can do' is different from the meaning others project on them.
The First-Generation Immigrant, because somebody in our world is already called 'an alien' wherever they are, on the daily.
The LARPer, spending every Saturday adopting a completely different persona from their own that engages in pretend conflicts for fun.
The Taxi Driver/Doordasher, providing a service with a vehicle that others want and still is often erased as a person for it.
The Environmental Engineer, because vehicle-dominant design is bad for Earth, yo! But does it change if we're talking huge people and not what's crowding out people?
