Why this movie is weak

Do you understand that your "list of reasons" is a hugely preposterous post?

It's like 'The Terminator (1984)'.

Basically there's a solid movie with a thought-out story.

The sequels then either copy that story and dilute it in the process, or make a story OUTSIDE of the interesting parts of the original story, and fail to be entertaining or interesting (or make sense).

The sequels to Back to the Future should never have been made, the first movie is nonsensical enough.. they should never have gone to the future, as they only had to have knowledge that would have changed the future anyway, they didn't have to go there.

It's hard to believe that Marty wouldn't warn his son about Griff's stuff, like.. what was Marty thinking?

Yes I agree, it's exactly that.
A heartfelt compliment, like when Bill Gates complimented Jobs on the first macintosh by saying
"I like it. It's the computer I would buy for my mom."

I like it ok, but most of what I like in it comes from the previous 2. I expected more.
Most of the new ideas feel out of place or pale repetitions of previous ideas.
I wish it kept the bar as high, but it could have been worse too, so ok.

"Back to the Future (1985)" is a pretty good movie, as far as entertainment, atmosphere, funny feel and all that is considered. A nice premise, cool effects, great 1980s magic..

Of course when you look at it more objectively or take away the 'magic' aspect of it, and the premise (that really goes nowhere - it's a lot like E.T. in that someone is 'stranded' somewhere (or somewhen), and just has to get back, and does at the end, close curtain), you're basically left with strangely incestuous story with a lot of filler and kind of weak basic core.

Marty goes to past, then tries to get back to present, and does. His running around in the fifties alters the timelines, so that the other Marty has to live a miserable existence in poverty with weak dad, alcoholic mom and dead doc, while 'our Marty' that we see the adventure of, steals the other Marty's life, riches, girlfriend, family, car, etc. and as a bonus, even gets to see Biff as a weak and supplicating man in a non-threatening position.

When you think about it, the movie isn't that interesting, nothing that much happens, it doesn't expand your thought, it doesn't go to wild adventures in different times, it doesn't really explore what time really is, and in how different ways you can think of it (in the part II, Marty's past happens in the future, so is it past or future? There's a 'personal timeline' that's separate from 'everyone's timeline' - but none of this is really explored).

The potential is wasted in some silly 'get your parents to fall in love' story that's not very interesting (the movie is just so well done, and so intense, it seems interesting). Why is it always a 'love story'? I'd rather have seen exploration of different times, and how future knowledge can make living in other timelines fascinating, etc.

But it's just a typical 'stranded' trope that gets back home in the end. Nothing new, nothing too interesting.

Now when it comes to Back to the Future Part II, it's _EVEN_ thinner storyline!

That sums up my same sentiment for this.