PREFACE: I grew up in the 80s. I didn't give much of a fuck about Transformers because I could not regularly watch the show due to growing up in the sticks (I had like, 3 TV channels. 5 on a cloudy night)
In short, I gave ABSOLUTELY ZERO FUCKS about any sort of "nostalgia" element because it just didn't exist for me.
I remember seeing Bay's Transformers 1 about a year or so before Transformers 2, and I saw it incidentally, not intentionally.
The film agitated and annoyed me a bit at parts, but never to the point of outright hatred.
Shia LeBouf and Megan Fox were both terrible, and their characters COMPLETELY WORTHLESS to the movie as a whole.
I did not give one fuck about either of them, and was mercifully able to ignore them for most of the film so they were largely a non-issue.
The action, while a schlocky CGI boom fiesta, was fine and I even chuckled at some of the really stupid jokes.
Hell, I even found Bay's fetishism for the US military refreshing in a bizarre way: most films with aliens/giant robots/monsters tend to have the human military element (if any) playing the part of useless cannon fodder to be helplessly crushed by whatever force is at hand so we, the HUMAN audience, can feel their supposed powerlessness and incompetence projected onto us in a cheap attempt at provoking a response or some sort of tension.
Personally, I find that trope annoying and a waste of time.
Bay letting the military "win" a few exchanges with the Decepticons (even if for the wrong reasons) kept me interested because it showed that they had some sort of agency, and that they actually mattered a bit (even if they were ultimately losing without the Autobots).
So in that, I'll agree that Transformers 1 wasn't a great film on its own, but it also wasn't terrible.
Unfortunately, it is still the gateway film to one of the worst pieces of cinema I've seen.
Transformers 2 that pissed me off. A lot. Everything that was annoying in the first film was amped up and made central in the sequel. I didn't even bother seeing Transformers 3, because I could not bear the thought of giving more money to the same gumshit assholes who made Transformers 2.