I kinda got the feeling that her cleavage was there to balance out the Cruise shirtlessness.
You'd feel cocky too if you were full of myself.

To each their own. I don't find her to be the most gorgeous woman out there, but there are times her doe-eyes do it for me.

I see, maybe I didn't notice because I don't find Rosemund Pike to be all that attractive (by Hollywood standards) and her character in this was about as sexy as Uncle Fester
I'm gonna refuse you an offer you can't make

As the OP said, she was wearing tight sweaters which showed off how full she was - she was pregnant during filming. He didn't say she was topless in the movie.
One of the scenes in her office there was a shot of 'cleave-land' some nice bouncing going on when she ran down the steps to chase after Reacher.

I didn't even notice her breasts so I don't know what you're on about, they were covered up throughout the movie unless I'm mistaken (re watched it yesterday)
I did feel her character was a bit annoying though, Pike is not a bad actress she's proved that in GONE GIRL amongst other things but yeah I didn't like her in this one
I'm gonna refuse you an offer you can't make

you could be right about her casting, other than that i thought they made the movie really well, and tom cruise did a great job playing a character im sure a lot of book fans didnt like him being casted as. i didnt find her very attractive but now that you mention it, boobsssss every scene

As long as she's not in court or with a client, what difference does it make?

Yes in a couple of scenes her top was covering her breasts a few seconds later it way low as if someone pulled it down not a very professional look for a litigator

And the fact that during the filming of Jack Reacher, she was pregnant and her breasts were larger.

But I find it odd, that as the Title character of Gone Girl, even when 'vamping' she seems 'smaller' or at least more Modest, than she does here as a presumably professional woman.
It's all about how the character is written.
faith begins at the end of your comfort zone.

That explains it - she looked bloated. Face, boobs, legs.

She was pregnant during the filming of Jack Reacher.

no arguments But I find it odd, that as the Title character of Gone Girl, even when 'vamping' she seems 'smaller' or at least more Modest, than she does here as a presumably professional woman

She is remarkably well suited for tight sweaters and low cut topsbut it's way okay with me.

When I first saw the film I joked about it starring Cruise, Pike, and Pike's Cleavage
That said I don't think they Won her the role But I would not be surprised if they contributed to a rewrite that saw her become a composite of 3 instead of two book characters

Sandy was "Pittsburgh cute". Meaning she'd be the weeknight B crew stripper here in TX.

She has a hell of a rack which she uses to her advantage. If you have assets like these, why not use them. Plus she added a little eye candy to the movie. No one mentioned Sandy. She had quite a rack also and was very cute.

During the scene where they're piecing together the Oline Archer story, she's wearing a top that's essentially a display case for them, and a few shots have her in a position where it's like "The American Breast Council would like to remind you that boobs exist."
This scene:
http://imgur.com/a/BBtt4
Philo's Law: To learn from your mistakes, you have to realize you're making mistakes.

Why there are many many many comments about Rosamund Pike breasts in this movie?
Why did you go see Inception five times? Because you really liked it.

why there are many many many comments about Rosamund Pike breasts in this movie?
i mean you could see them for just a few seconds in that scene you are talking about
i think if she was topless people would not talk that much about her breasts and there are many people talked about that scene before.
i went to see INCEPTION 5 times !!!