The correct answer here is the jump from 16 bit (snes,Megadrive etc) to 32 bit/64 bit (PS1, N64 etc).
While I understand the appeal of saying that the PS1 > PS2 (And other consoles respectively) was a bigger jump because it consists of somewhat rough approximations of worlds and characters turning into much more detailed worlds and characters,
it's simply not anywhere near as big of a jump as the jump from 2D games to 3D games were. It was quite literally, video games reinvented. Video games went from 2D "Games" to 3D worlds. And they were exploreable as well. The example of
Banjo64
is an excellent showcase of just how large that leap was. If you want another example, put Super Mario World next to Mario 64 and then place Mario 64 to Mario sunshine and ask yourself: Was that 2nd jump really as big? The answer is No.
There will probably never be another leap as big as the Fourth gen to the Fifth generation.