Uh-oh. Better tell that to Transformers: Cybertron (Cybertronian jet form) and Transformers: Animated (SUV).
Seriously, people, the claims you're making here are laughable.
Robots In Disguise: Koji, Dr. Onishi, Kelly.
Armada: Carlos, Rad, Alexis.
Energon: Kicker, Misha, Sally (along with Carlos, Rad and Alexis in a more limited capacity)
Cybertron: Coby, Bud, Lori
Animated: Sari (although technically not), Sumdac, Fanzone
Prime: Jack, Miko, Raf, Fowler, June Darby
And I really enjoyed the Michael Bay films. Even Revenge of the Fallen, which admittedly is the weakest of the three. But I can't be alone in the chills I got when the Autobots drove up to Sam and Mikaela for the first time and all transformed. Hell, I still get chills thinking about it now. I honestly think it's just "cool" to hate on anything Michael Bay does. The hate borders upon hipster-esque.
What I always found amusing is that people would bash the Transformers films using the exact same reasoning that they would praise Avatar.
Transformers: "Well, yeah, it looks really great visually, BUT OMG THE WRITING AND PLOT SUCKS SO HARD OMG!!!11"
Avatar: "Well, yeah, the writing and plot are pretty bad, BUT OMG SO PRETTY PRETTY PRETTY!!!11"