Quixit :
If you're interested in gaming, don't buy any kind of all in one computer. They're barely upgradable and generally use notebook GPUs, which are much slower than desktop GPUs.
Same way with CAD design. Even laptops/AIOs with Quadro cards pale in comparison to their desktop parts.
AIO are just overly glorified laptops as the hardware inside is the same. If you're looking at size, consider doing a mini-itx build. If screen and computer combined is more important, glue a monitor to the side of a computer case.
You'd be much happier with the results in both cases.