Yeah if you're trying to run exe files you're just going to make a windows/dos clone. Whats the point in that?
The only Windows clone being actively developed is ReactOS, and it's unstable as hell.
Windows is still the de facto standard OS for PC.
This is like telling hardware guys back in the '80s that developing an IBM clone was a waste of time.
As braindigitalis said, you need an awful lot of work to get to the point of displaying graphics. Even writing your own 2D framebuffer drawing code is a considerable challenge, but you also need to write your own graphics driver.