My PPC (Willcom WS-003SH) has a sliding keyboard, so I usually use it in landscape mode. The D-pad is small and downright hard to use, so when using Stackz i prefer the touchscreen buttons.
As seen in the attached picture, these buttons take up about one third of the screen, and as much space as all attributes combined. Even so, I still have to use the tip of my fingernail when hitting the up button to be sure that I don't accidentally hit any of the adjacent ones.
A possible solution to this problem would be to make the buttons an invisible 'overlay'. This would free up a lot of screen real estate AND make it easily maneuverable with your fingers.
Another problem is that, since font size is decided by attribute length, "entry" and "reading" will get a huge font while "example sentence" will get a tiny font, and still not display correctly, since only the first line is shown. Switching to portrait mode will fix this, but being able to 1) choose font size, or 2) redistribute the height of attributes would be a lot better IMO.
Landscape mode:
Portrait mode: