The rope is the same, it's the input code that did weird things, which caused it "not to be the same", such as "framedrops" of keypresses.
WA and WWP ropes are identical at their code base. The physics are the same. Worms2 is the only one that's different, and in many ways. Also note that the "improved rope" feature of RubberWorm only simulates a very small part of the Worms2 rope (such as angle and acceleration), and not its unique physics.
I was initially going to reply after Aerox's first comment, but I hoped the thread would calm down on its own. Seems like I have to post this as there's still lots of misinformation in the air.