Agreed with everything mentioned except Bumblebee. It was not a plot hole as Sam said Bumblebee is 'playing it up'.
The problem is people bitched and moaned whether they gave the bots differences of personality or not.
IMO keep Bumblebee the way he is. There is nothing wrong with him. Why mess up a good thing to see the same people who whine about him not having a voice to only whine when they hear him speak?
I agree with Epicbacon about the human aspect of the films but its not going to happen. I'd like a more even balance for sure but the human vehicle will carry whatever story they decide to put forth in a new film.
Leaving Planet Earth is highly unlikely. These films are designed around real world encounters. Seibertron I can see being used here and there in flashback or some restoration storyline but for anyone hopelessly hoping for complete removal of earth, humans, military are likely not going to get it IMO.