I wonder if anyone even pays attention to this site anymore. Whether you read this or not, though, I want to say it.
It has been seventeen years since this editorial was published. I discovered the Transformers two years ago. I fell in love for the very reasons you have described - the fans and the characters. Not the plots of any of the media, or even the giant alien robots aspect (though that was and remains a draw), but the people.
And characters may change in appearance and behavior from show to show, but that doesn't diminish what they were previously. An example: G1 Prowl and TFA Prowl. Prowl is my favorite character, and these two versions of him are extremely different in behavior, skillset and appearance. Yet in more recent works, I see a Prowl who looks like his G1 frame, serves as a tactician, and yet practices martial arts and has a great respect for nature.
The fandom is strong. It takes in new fans and remains strong. The core is the same as it was seventeen years ago, and I have found a home in it.