Your new harness and cart are gorgeous, where did you get the harness if I may ask? I am shopping around for one for my new guy!
I agree with MajorClementine that the shafts need to come up more. Also, just more of a personal preference thing, I would tighten the breast collar up (not the tugs but so it sits higher on her) a bit. In my personal experience this allows the horse to trot out more as it frees up their shoulders. I teach my horses to pull from the center, not relying on the tugs so usually when they are collected the breast collar and tugs get loose freeing up their shoulder and allowing them to move freely.
You should start posting videos/pictures in our Drive Day topic