+1 on the just swap out the saddle on the FX as it seems like you really like that bike. It should be super easy to do that yourself but usually the bike shop would do it for free if you buy a new saddle at the same time. They might even do it free after the fact too. The 7000 series is more of a comfort bike, like a high, high end cruiser. They have really wide tires.

You might want to try out the Giant hybrids too which are called Dash in the women's version. They are basically equivalent to the Trek FX line. I happen to be a Giant fan and I ride a FCR3 which is an older version of the Dash. I use it as a "fitness" bike to exercise and I sometimes commute on it. It's comfortable (enough for me anyway) and I can almost keep up with roadies on it. :-)