This becomes a metaphor for the human psyche. The ability to reason is meant to separate beasts from humans (and in this case, other high-order sentient beings like Transformers). The Dinobots often have difficulty controlling their more primitive and savage impulses - Slag is the worst of the lot, but the others suffer from it too. Grimlock is notorious for having violent rampages and tantrums; like when he trashed his quarters aboard the Ark due to his frustration over his fellow Dinobots being in stasis lock, or when he decided to engage "aggressive negotiations" with Thunderwing during the Matrix Quest and likewise with Fangry during the Autobot-Decepticon Alliance period. Grimlock is clearly an intelligent being in the comics, yet he does occasionally allow his rage and passion to get the better of him. And many of the other Transformers do likewise - when their emotions break beyond a certain point, they just get miffed and go ape.

But none of them ever become like Slag though. None of them ever go into a true Berserkergang where "the berserk seemed to lose all human reason, a condition in which he could not distinguish between friend and enemy" (ref). While some may become insane with power and turn on their own allies (such as Underbase Starscream and Dark-Matrix Thunderwing), they were still inherently still in control of their faculties where they were able to discriminate between friends and foes - in the case of Underbase Starscream he consciously chose to turn against his fellow Decepticons (the distinction no longer mattered to him) and in the case of Matrix-Thunderwing, he immediately regretted shooting Spinister, but the Matrix soon consumed him and he was no longer in control of his actions. Thunderwing never became a Berserker, instead the Matrix itself had become a force of evil.

Shockwave is arguably on the opposite end of this spectrum - a Transformer who has honed his abilities of reasoning so much that he has nearly (but not quite) absolved himself of feeling emotions... dedicating himself purely to the laws of logic. There are times when his emotions get the better of him, but he quickly reels himself in and decides to do what "logic dictates"... unless he encounters a logic paradox which he cannot compute/resolve, then his rational mind kinda semi-shuts down and he is at a loss as to what to do. Jhiaxus also tried to attain a similar state of "logical enlightenment" but unlike Shockwave, he had serious savage primal fury bubbling under his facade. Jhiaxus isn't quite as bad as Slag's Berserkergang - he can still distinguish between factions... but he will abandon nearly everything else; his cause, his mission, his duty and endangering the lives of his fellow Decepticons etc. - he becomes completely enraged and so irrational that nothing else matters. Ironic that he became the very thing that he was trying to eradicate from the universe.



And as you've alluded to, the movie continuity points out that the Transformers do have a primitive savage trait that they've learned to evolve from, hence:
Ironhide: "Why do we fight to save the humans? They're a primitive and violent race."
Optimus Prime: "Were we so different? They're a young species. They have much to learn. But I've seen goodness in them. Freedom is the right of all sentient beings."
(and the audience cheers )