A1: faust, and his adds will hit harder, preventing the team from ignoring adds.
Oppressor's proximity damage buff will be permanant, and they will hit harder. new mechanics added (?). spider adds will require less debuff stacks to get the effect, 3k tonze missile will wipe if it lands, and have a tighter dps check.
A2: everything hits harder. Jagd dolls buff eachother. spider tanks might have mechanics like dreads from turn 4.
A3: edge probably will guarantee your death if you land in it, human form will probably always require a tank swap. all mechanics less forgiving. vortex form adds might act like ifrit ex nails.
A4: i don't even want to think about it.