To begin with, I want to express my appreciation to everyone who has contributed to FreeCAD. It's worth a lot to me to be able to do some hobbyist CAD work using a project that I can realistically hope to influence or contribute to, to make it better.
I'm a complete hobbyist, I've never done CAD work professionally and have some limited experience with 3D modeling software, Cinema 4D, Modo and maybe some others I don't remember anymore. I just started toying around with FreeCAD and I have a lot of gripes with its UI I could share my experience with, but I don't want anyone who worked on this to feel like I'm not valuing their work. I'm trying to concentrate on those issues I think could improve the experience I've had so far the most. I'll focus on 2D and 3D navigation here.
I've found that none of the navigation modes work for me. I can make it work with an external mouse but I never use one on my laptop. I use a MacBook Pro with one of those trackpads that don't have separate buttons. I really like it and feel comfortable using it for hours at a time but it does have some limitations input-wise. E.g. there's no middle-click, there's a right-click, but it is impossible to combine with left-click and dragging with right-click is very awkward.
So the OpenInventor, CAD, Revit, Blender, MayaGesture, Gesture and OpenCascade are all out of the race for me right from the start. I was unable to use any of those to both rotate and pan the view. This leaves only the Touchpad mode. But that mode feels very unnatural to me.
The hardest to get used to for me is the combination of "grabbing" the view with the shift key while moving it with the mouse. I think there's a very good reason why other types of application (maybe all other application I use?) always require a mouse button to be pressed to move something with the mouse (be it an object or the view). When I try to do these movements quickly, I can't get pushing the shift key synchronized with my mouse movement, which means that I either press it too early, moving the view in the wrong direction for a fraction of second or I press it too late, not moving the view the whole distance of the mouse movement. When doing these kinds of things in other applications, or even games, I never have such issues. And I in no way feel impaired when it comes to using a mouse or trackpad.
OTOH there are some missed opportunities here! The trackpad on my laptop supports very fine-grained scrolling movements in 2D, so that could be used for panning!
I'll tinker with some other graphical editing applications I use and gather write up what I would change in another post.
Thank you for reading so far!