It's weird to try and reboot a franchise only 3 years after the last installment but it's even weirder to let it be done by the same director. It indeed also feels more like the same really, which is not a very good or positive thing to say, since that also means that the movie is falling into the same traps and is making some of the same mistakes.
So there is a different cast who all portray some different characters this time around but does it really matter? In my opinion human characters will always seem irrelevant and meaningless in a movie that's all about giant robots clashing in to each other. It's also the main reason why none of the human characters ever work out very well within any of the Transformers movies. They besides aren't developed- or likable enough and it feels as if they get too much in the way of the movie its action and true story, that concerns the eternal battle between the Decepticons and Autobots.
Thing about the characters also is that there are far too many of them in this movie. It's all part of the reason why the movie tends to feel overlong and messy at parts. It's definitely true as well that the movie is lacking a good main focus in it. I honestly can't even tell you what its main story is supposed to be all about. There constantly is a whole bunch of different stuff happening in this movie but at the same time it isn't ever telling you an awful lot. My guess is that this movie got written with a few big action set pieces and 'new' Transformer characters in mind and it was up to the writer of the movie to base a story around these set pieces and to somehow connect all of them together to each other. It only makes the movie feel disjointed and confusing to watch though and it's hard to stay interested while watching the movie.
Yes, it may sound weird but the movie actually becomes boring to watch after a while. It doesn't matter all that much that there are big explosions, fights scenes and car chases every 5 other minutes. None of this matters much because of the simple reason that you'll just wont ever feel emotionally involved with anything that's happening. There's never a good sense of danger, mystery or urgency and you don't know enough about any of the characters or their backgrounds to care about what happens to them and that includes all of the different Transformers. Also please don't ask me what different Transformers appear in this movie, since I have absolutely no idea. They all look and act alike to me and just like the human characters, there are a few too many of them. I know that some people are excited about seeing the Dinobots make their appearance in this one but their presence adds very little in my opinion and they aren't even in the movie for all that long. They fail to make much of an impact but the same of course could be said about this entire movie.
And I am actually OK with Michael Bay doing big, dumb, overblown, expensive action movies and I genuinely enjoy some of his earlier movies but the one main thing that always bothers me about his movies is the 'humor'. It usually just involves a character talking in a fast way and saying stuff at inappropriate times, that just isn't all that funny or witty at all. The only time the humor actually did work out well within a Bay movie was "Bad Boys" but looking back at it that really must have been due to Will Smith and Martin Lawrence, who of course know how to do and handle comedy. Without experienced and talented comedy actors, Bay is nowhere. That once again becomes painfully obvious during this movie. The comedy is cringe worthy and makes the movie even more ridicules and painful to watch at parts.
Still I'm not going to give the movie a terrible rating as well. Even though it clearly isn't for me, there obviously is a big market for this movie and it serves this market well. It gives the people what they pay for and that does not include a great story, rich characters, strong emotions or brilliant acting. Most people who pay to watch this movie expect to get lots of spectacular visuals and tons of simple, mindless entertainment from it. And sure, visually there isn't an awful lot wrong with this movie and I have to say that it's great and impressive to see how special effects keep on improving. The Transformers look better and more 'realistic' than ever before, especially in terms of their facial expressions and how they move around. Also if you like big explosions, exaggerated action and tons of slow-motion there is no denying that you are probably still going to enjoy this movie, regardless of everything else.
I don't like it but its target audience probably will and that in the end ultimately is still what matters the most.