Thank you so much for the quick and kind reply! I love that some of the stuff is already on the to-do list! :) Will definitely support it going forward.
I've linked below an example of the preview window. It's from an abandoned app called SpritePile on itch:
https://www.youtube.com/watch?v=s356D76-nFQ
It has the option to the show a preview window on the bottom right which is constantly rotating while you're building. A few similar programs also have this feature.
Also one final suggestion to add is a shape/geometry tool in addition to line tool. So that we can create flat or 3d boxes/spheres easier! Cheers, and thanks again :)