Which terrestrial planet would have its surface temperature the most dramatically changed if its greenhouse gases were removed from its atmosphere?

Venus. The atmosphere of Venus, in fact, is full of carbon dioxides, the main contributor to the dramatic greenhouse effect on the planet, which causes the surface temperature of Venus to reach 460 degrees Celsius. Without this effect, the surface temperature of Venus will be more similar to Earth's one (still a bit higher, given the smaller distance from the Sun).