The original Anchorman is apparently a cult classic, though I've never seen it. So I have no idea if Anchorman 2 is funnier if you've seen the original. My bet is, probably not, because half the time it didn't even seem to be connected to itself, let alone anything else. Anchorman 2 is not so much a movie as a whole mess of things getting tried one after another. You don't like this bit? Never mind, maybe you'll like the next bit. Rinse, lather, repeat until it's over.
The one really good bit comes right at the end, when parody versions of every "fact-based" tv product in existence meet for a duel to the death. It's not so much that it's funny, as that it turns into a parade of guest stars. First Sacha Baron Cohen is there as the BBC, then it's Tina Fey as - actually I forget what they were supposed to be, then it's Liam Neeson as the History Channel ("It's news, but older…") until finally Marion Cotillard is swearing and apologising as the Canadian Broadcasting Corporation. There's a moment in one of the Batman movies where the Joker shakes his head and asks rhetorically "Where does he get these toys?" and I was doing the same head movement and wondering where Will Ferrell gets all these guest stars?
Anyhow, buying them all donuts meant there wasn't a lot of money for a script, and so the movie's all over the place. Everyone's going to be laughing their heads off at ten minutes of it and everyone's going to be annoyed with another ten minutes; just a different ten minutes for any given person, so you wind up with the cinema laughing quietly all the way through instead of all at once at the big pay-offs.
Which is fine, I guess. It was that or 47 Ronin, and at least when Anchorman 2 was ridiculous they were doing it on purpose. In a way, the biggest problem is that the movie's too true to be funny; it's parodying 24 hour news, and since 24 hour news has by now gone beyond parody, all the stuff we're shown doesn't seem like a stretch any more.