It depends. If you're using it in a negative statement, it tends to connote a woman who isn't very smart. If you're making a positive statement, I think it would be roughly equivalent in formality to calling someone a "babe," without the connotation of being pretty. So still don't use it to talk about someone in a professional context.

Probably older, probably more experienced, subject of a news story, in a fairly professional context? Kind of offensive (IMO).

I think outside of common terms like "chick flick", this is just like using "girls" to refer to adult women - think to yourself, if you replaced the term with something like "boy" or "dude" how would you sound?

I don't really go on crusades about these particular uses of words because I feel there are better fights to fight, but I would never refer to a man in this particular context as a dude. Maybe I'm overly politically correct, but I try to be respectful to everyone.

In this context it reads as highly dismissive.

About as offensive as "geezer" or "cracker".

Absolutely depends. Some people find "chick" just about as offensive as "nigger", while some people don't care in the slightest. I've known a number of women who freely use "chick" to refer to themselves or their friends.

If you're a PC douchebag who actively seeks out opportunities to be offended by things, then, sure. Otherwise, I wouldn't recommend it.