Sketching a picture can help for certain classes of problems, but I think that is far from universal: it often tends to be of less use for logical concepts than structural ones, for example.
Beyond that, though, even when a sketch is a useful tool, I find I seldom use the computer to create it. A whiteboard, notebook, or back of an envelope all seem easier than working with typical graphical input mechanisms that are commonly available. Good touchscreens are a step in the right direction, but still far from perfect and far from universally available, especially on desktops. Aside from any innate problems with graphical programming in general, I think this input problem makes the approach generally unappealing at the moment. It's not an insurmountable issue, but until there are good input mechanisms that are as common as keyboards, I think you will just find that it is hard to reach the critical mass a new representation needs.
I know that input speed is not really a limiting factor in most programming, and maybe shouldn't be the deciding factor, but given how attached to their text editors programmers already are, and how disruptive and frustrating it can be to have to switch, I think it's clear that it is an issue.
Beyond that, though, even when a sketch is a useful tool, I find I seldom use the computer to create it. A whiteboard, notebook, or back of an envelope all seem easier than working with typical graphical input mechanisms that are commonly available. Good touchscreens are a step in the right direction, but still far from perfect and far from universally available, especially on desktops. Aside from any innate problems with graphical programming in general, I think this input problem makes the approach generally unappealing at the moment. It's not an insurmountable issue, but until there are good input mechanisms that are as common as keyboards, I think you will just find that it is hard to reach the critical mass a new representation needs.
I know that input speed is not really a limiting factor in most programming, and maybe shouldn't be the deciding factor, but given how attached to their text editors programmers already are, and how disruptive and frustrating it can be to have to switch, I think it's clear that it is an issue.