Just a quick thought I had chatting with Rouse of the saints in our league.
A potential change that shouldn't be too difficult to implement would be the ability or option to flip a play when adding it to the playbook. Or having an option to run the play in different sides....ie if you have the x run a cross and the y a post, have the option in the playbook to run that as a default, or flip it so that the x runs the post and the y runs the cross, or have both of those variations in the playbook and potentially weight each flipped variation
Also, please, make it easier to look through the entire playbook you run without scrolling, and grouping by formation or by play type (run/pass).