There is certainly a lot more variety in the missions, and now the story fits the gameplay better. When fighting invading aliens it makes more sense to have an army instead of a small team fighting against it.
And soldiers can look a lot more unique now. At least men had beards to create more variation, but especially women tended to look quite similar in the last x-com game.
With guerilla warfare it also makes more sense to have a larger number of women in the ranks due to what is at stake.