You've done a great job with your layout already. Your options are limited with the sectional unless you want to try breaking it apart. What is probably bothering you is the wasted area by the doors. Backing a table up to the sectional and placing a couple of comfy chairs on either side of it, looking out to the yard, would be a useful and attractive option.

I like that concept and I'm completely open to new furniture

actually I would rather buy new furniture. If you had it from scratch what would you do?