Moving will be made to interrupt spellcasting at a point in time...

[Betelgeuzah]

Or you would stop moving and begin casting (on your end it looks like you did it right) but with the server lag it would actually have you still moving forward slightly...as you try and cast...getting you to the final moment of the cast to see it just get cancelled.

That always drove me bonkers! (which is why I stuck with SCH since you usually had to use an ability THEN cast so I didn't run into the problem as much)

Well, that won't happen in 2.0.

Finally Yoshida provides a wall of text I am genuinely interested about, though. Hopefully more to the point than the last time(s).