After hearing all the horrible reviews, I still wound up going to see it. Those reviews normally lead me to enjoy a movie more, due to setting expectations low. Since I was already not expecting much, those reviews dug out the basement to establish a new all-time low. That pretty much saved the movie for me.
For instance, I've heard the film dragged. For me, while I could see a lot that should have been left on the editing room floor, it never really made me want the film to pick up the pace. There have been complaints about not being able to differentiate between many of the Transformers, it was much improved over the last film and, where there would be confusion, there's really nothing that can be done to prevent the issues.
The one issue that there's no getting around, however, are the racially stereotyped "Twins". Two Autobots that could genuinely be considered the "Step & Fetchit" of modern day flicks. Gold teeth, slang and the whole nine yards. The problem, though, is the lack of an actually assigned race to machines. In many current movies, if you slap that particular set of characteristics on to a non-black character, you generally get a bunch of people laughing and no one crying foul. So we have "raceless" machines with these traits. That's where they obviously thought they'd be OK, but clearly where they cause their problems. Without an assigned race, interpretation will revert back to the race that the stereotype is about.
For what it's worth, though, the audience in this showing was of diverse ethnic backgrounds and the laughs at the antics of the Step & Fetchit twins were loudly coming from all over the theater. So whether actual mainstream America will make an issue of this or it will just stay with the critics and the talking heads remains to be seen.
The other noticeable bit was the generous helping of profane language. I'm not a prude, but you hear so many curse words coming from a flick that, from my understanding, is supposed to aiming for kids as well as adults, each time one pops up, it grabs your attention. Fuck, shit, asshole and pussy all wind up getting thrown around liberally.
One or both of those issues will be grabbed by a conservative values group to make hay over, I believe. I doubt that aspect will really have a negative effect on the film. I can respect the racial one being strongly objected to. But when it comes to the "I can't let my kid watch that" crowd, they generally need to realize that vetting stuff for their child's viewing is their job as a parent. On top of that, companies need to realize that those who protest on these sorts of things are often not the consumer it was made for to begin with, so they're not losing patronage of their product.