Megan is a poor excuse for a reporter

Really? You're a genius

In spite of what Newman's character says at the end of the movie; the character of Megan is a lousy reporter.

Although instructed by the paper's lawyer to make the effort to contact Gallagher for his side of the story, she obviously doesn't or just goes through the motions and makes a half-hearted effort.

She asks Gallagher the name of his boat when it's plainly printed on a life perserver in plain sight (not very observant.) She asked him the name of the boat because she was taken on the boat and didn't know what was going to happen to her, so she asked that question so her tail could report it, which he did, as the police helicopter flew above and asked who she was and if she was okay.

She figures out that Rosen left the file for her to see, and later in the law library scene she acts like it's a sudden realization. No. She just decided to out him.

And for some foolish reason tries to persuade another reporter into downplaying a shark attack. A paper's function is to inform the public, especially when public safety is the issue. Papers have no obligation to the Miami tourist board. She was being sarcastic and a little bitter, feeling sorry for herself is all.

All in all a pretty pathetic excuse for a reporter.

Her editor was also just as bad.

Swing away, Merrill....Merrill, swing away...

That's a big theme of the movie actually.

Actually she's a hell of a reporter. She energetically follows leads and knows how to get information she needs; she shows great intuition and has a very tight grasp of what constitutes a good story. To quote Gallagher, she's one hell of a reporter. But for all the reasons you cite, she's a lousy journalist. And yes, her editor, whom she seems to see as a mentor, is a lousy mentor. I believe this is a point of the film.

"A paper's function is to inform the public"

You haven't been paying attention the last few years. A paper's function is to advance its ideological agenda by misinforming, or by not informing the public. Maybe it was different back in '81.