So, I finally saw this movie, and like many fans of the original TV show and Disney channel original movies I was disappointed. I think the biggest flaw was that they changed really heavily established lore, trying to make a completely different movie, based on the same basic idea, which I didn't think was necessary. Additionally, they some how, even though they changed everything, lacked originality with the same, seemingly perfect person, distracting Kim from her crime fighting job, who ends up being fake, which was done in Kim Possible: So the Drama, differently, but also the same.
Now, here's what I would have done, First, still make it freshman year, but make it the freshman year before the original show starts, and that includes making it "take place", roughly with 2001 era clothe, phones, lingo, etc. I think it would have been fun to see, and I don't think it would alienate the new audience as much as Disney Channel might have thought it would have. Also, create a new villain, preface the story around the villain before the ones we see in the show, what was Kim Possibles, warm up challenges before she got Dr. Draken in the first episode of the series. Lastly, still make it about Kim Possible figuring herself out, just not inspire of someone else. Yes, she's figuring out she can do anything, but having the confidence to claim that would still be a journey. it's still her tagline, but she's figuring out how true it actually is. Remember, there is only about a year or two from the "Stich in Time" - First real mission, (12/13) to the beginning of the show were she's a confident world saver (15). That's a steep learning curve, they should have explored that, that is a story.
And while the movie was bad, it still maintained little bits of the feel of the original show, which was nice, but it was defiantly trying too hard.