are you quilting on a frame? Or, are you using a portable sewing machine and doing freehand?
The last round could definitely be a different design, if you are bored? The biggest critic you have is yourself! Everyone who sees it when you are done will think you are the most talented, capable human on earth!
I know what you mean about being bored with straight line quilting, so it sounds like you are ready to break loose and really move that fabric! (or the quilting machine if that is the case) ...
I think a big stipple around the border would be very interesting, or anything else you choose.