I think it will be 2-3 months of down time like after the bot nuke.
No, this isn't messing with any of the internals (atleast that we are aware of), so the only difference will be combat, a few widgets and other things, mainly it'll be a hassle for non combat scripts as we'll have to re-write some/most of it. And combat scripts will have to rewrite quite a bit of it (not sure if they'll be using momentum or actually using abilities)
Combat without abilities is like using a bronze longsword in the live game. It's 500 times faster if you use abilities efficiently, so I'm sure the scripters will quickly get it figured out.
It will mess up combat scripts obviously but perhaps not non-combat scripts. apart from of course the update which will take a day/2 to overcome but that's normal.![]()

