The main thing that would make life a lot easier is the movement and resizing shown in the video. It allows for you to move blocks in all dimensions without having to have your camera in certain spots, and you can resize them in any direction from any given position.
I can't see any good reason to have the blocks follow the mouse like they do, compared to having the very simple and versatile resize/movement arrows. The "arrows" also help with precision since you're moving them along one axis at a time, looking at any angle or distance you want, as opposed to dragging them on a surface or having them snap to it
Now, I'm not trying to say that the current mode is terrible, or that the one showcased is completely better, but I do believe that something like this should be considered.
Also, I'm not here to defend FtD but its features for building components and weapons allows for more thought to be put into designing ships with defined purposes and building a good mixed fleet. I'd prefer custom turrets over the attachable turrets like in Avorion because they allow for ships to be built around a function, but of course something like that would not work at all with how ships work in the game and it isn't really like Avorion needs to be a tactical ship designing contest anyway.
In the FtD example I was referencing how it has two build modes, one a simple easy-to-use one, and another meant to better suit the gameānot saying that any of its mechanics should be borrowed (the two games are extremely different in both form and goal, after all)