Ghosts powers are either on or off, Vision moves through different levels of density to achieve intangibility.
Visions body seems to always change as one whereas Ghost can phase individual parts of himself.
Shadowcat's power is different again ... partly bacause it's a biological rather than a technological power. She also disrupts electronic systems, neither Ghost nor Vision do that.
I cannot dispute with certainty what you have said but I will have to research that further. I will hold off on any arguments regarding that for now until I have facts backing me up. Gotta do my homework on this one.