With the addition of Ditto's new ability eccentric ditto can now copy an opposing pokemon without wasting a turn to transform. This is a massive change for ditto as it essecially means that ditto is effectively any pokemon on your opponents team at any time with ditto's HP.
Assuming the transformation is still the same as transform this would also mean that ditto could come in to a stat boosted poke and copy it leaving it to a speed tie to determine who goes first unless you added a choice scarf or the like to the ditto.
Edit: Therefore, ditto can theoretically effectively outspeed every pokemon in the game not holding a scarf with a choice scarf on turn 1
Discuss this change!