Much of what you describe sounds like a diminished follow-up to what the early part of Barber's run promised, but never delivered.
So I'm not quite sure how I feel about this storyline. A lot of what Optimus Prime does here feels off... imposing himself on Earth and murdering Galvatron to remove him and his influence from the picture don't seem like things Optimus Prime would do. The Titan he raised is unexplained as of yet, making it feel like a deus ex machina plot device, though a good reason for it being on Earth can solve that. "All Hail Optimus" is definitely a status quo altering plot in a number of ways, which I suppose was the intention. Maybe forming a combiner with Prowl has given Optimus some darker tendencies as their minds blended? Might it work both ways? That might well be a satisfying explanation and one I could accept.
Optimus has never been above killing. Even without Furman's idiotic back-writes, Prime was willing to sacrifice the Ark (without premeditation) in the original Marvel series. And, in the 1986 movie, Optimus was going to kill Megatron after their fight. IDW Galvatron (like any Galvatron) was a monster worth killing.
Prime taking over Earth was benign imperialism. Some people might be squeamish with that idea in modern times, but it has moral roots of a sort. (Prime's goal was to protect Earth.)
The other stuff could be explained by Prowl's influence (which may well have been part of original plan for the series).
"Revolution" was terrible. It was the realization of an idea that I (and most 80s kids) wanted to see since we first realized that many of our favorite cartoons were made by the same company. And, it was in a mainline book. But, IDW botched it on every level.