A Grey's Conspiracy?

I finally got around to watching the finale for Grey's tonight and I'm wondering a few things.  If Shonda Rimes knew at the beginning of the season how the finale would end, wouldn't she have wanted more buzz around the finale?  Wouldn't supposed unrest and unhappiness on the set create headlines? I'm just wondering if the whole Katherine Heigl and TR Knight spat about wanting to leave the show was done to boost viewership for the show or if I'm just reading more into than is there.  Heigl has made no bones in the past (supposedly) about wanting out of her contract to do more movies, but the T.R. Knight "wanting out story" didn't begin till this year.  Shonda Rimes didn't want to talk about her discussions with Heigl and Knight in her interview post finale with Michael Ausiello and was quite terse when the questions were asked.  The whole "are Izzie and George leaving?" storyline has been around since the supposed "leak" from the set of Grey's.  I'm probably reading too much into it, but one truly has to wonder.