Whenever people talk about the changes between SWADE and SWD, there always seems to be someone who describes the removal of Charisma as being one of the main differences. I don't agree.
There are hundreds (if not thousands) of sweeping changes between SWD and SWADE, and some of them are massive rewritings that can fundamentally change the way the game is played. But the removal of Charisma? That's nothing more than a syntax change, and it has absolutely no impact on the game.
In SWD, Charisma was simply a modifier that applied to Persuasion and Streetwise rolls. That's it. For example, Attractive gave you +2 Charisma, but it could just as easily have been written as "+2 to Persuasion and Streetwise", and it would have been functionally identical. I'm guessing "Charisma" was included to make the game easier to grok for players from certain other RPGs, and it made it a little easier to track on your character sheet if you stacked up a lot of Charisma modifiers. But generally, it was an unnecessary extra step, and I would have preferred to see it removed in earlier editions as well.
In SWADE, Streetwise was effectively merged into Persuasion (the mechanics from the old Streetwise skill became the Networking rule, which primarily uses Persuasion, although you can use Intimidation instead now -- note that there is also a Streetwise Edge in SWADE, but mechanically that's more like half the old SWD Investigator Edge, which was split into two for SWADE).
That means if SWADE had kept Charisma, it would have just been a modifier to Persuasion. So Attractive would have given a bonus to Charisma, and Charisma would have given a bonus to Persuasion. At that point, it becomes obvious how superfluous it is, and I imagine that's why they decided to remove it (and perhaps also the fact that there are now fewer Edges and Hindrances with generic Persuasion modifiers that you can stack).
But in my opinion, in terms of describing the changes between SWADE and SWD, the removal of Charisma is barely worth mentioning, and only really of historical interest to someone who picks up an older character sheet.
