Does anybody have solid information how Ditto is going to be handled in PvP? The cute but useless blob might have a HUGE impact on the PvP meta.
A perfect Ditto of level 40 with its CP of 832 should be able to start in any league. In battle it will keep its own HP, which at 117 after the rebalance is not too shabby. Enter a Tyranitar of level 13.5, with CP 1479 the strongest to be allowed in the lower league. Its HP is 117, by chance the same as the level 40 Ditto it is facing. But said Ditto will transform into something with the attack and defense stats of a level 40 Tyranitar - and will proceed to stomp the original into the ground.
In the 2500er league it will be a little better, as poor T-Tar at least has 30% more HP. But this is not enough by far. Dragonite and Metagross are even worse of, as their stamina is lower. Gengar can at least survive - barely - in the middle league.
If Ditto is allowed in PvP tournaments based on its original stats, without any special rules, it will effectively keep the top tier Pokemon out of the lower leagues.
As was said, Ditto isn't allowed in PvP.
This could be because it's very disbalancing - a CP 500 Ditto can transform to something really strong, well over the CP cap of the league.
This could also be a precursor to abilities, and some sort of changes that would allow Ditto to fight in PvP, but Niantic hasn't figured them out yet, so for now, not allowed.
Figures for Niantic to choose the most primitive and dull solution. Darn, I would have liked Ditto to mix things up. Now I can't help but predict DESPAIR, DEATH and DESTRUCTION! Also DOOM, DISASTER, DAMAGE, DULLNESS, DOWNFALL, DISSOLUTION, DAMNATION and DEVASTATION. Not to mention DITTODISCRIMINATION and DHESAURUSABUSE.