The update came out already and the Crossover has officially begun. I made a quick vid showing off some of the new characters for anyone interested, view it below.
All the Survivors got custom loudouts and voice packs and the models are remade as well.
The Witch also has custom moves, generally she is a Bloodshot but runs around instead of dodging from side to side and the jump counter isn't a one hit kill on her.
What you can't see in the vid (because I added a custom song from the L4D2 soundtrack) is that the Mercenaries music is also changed and when there is a Witch or Tank it changes to the Witch or Tank theme from L4D respectively.
EDIT: Here are the loudouts.
All the Survivors got custom loudouts and voice packs and the models are remade as well.
The Witch also has custom moves, generally she is a Bloodshot but runs around instead of dodging from side to side and the jump counter isn't a one hit kill on her.
What you can't see in the vid (because I added a custom song from the L4D2 soundtrack) is that the Mercenaries music is also changed and when there is a Witch or Tank it changes to the Witch or Tank theme from L4D respectively.
EDIT: Here are the loudouts.