You are forgetting the value of scouting.
So what, suicune pretty much screams cm, surf, icebeam/sleeptalk and rest. What advantage does ditto have against suicune. No scouting advantage If it stays in too long it must struggle in 3 turns due to pressure and choice-scarf, or switch out to let a teammember take a +6 surf before it can switch back in.
Even keeping Ditto in for that one turn allows Crocune to get a free switch in and a free Calm Mind. Double switching is still a good option and basically becomes a game of Rock, Paper, Scissors. You send in a bulky sweeper and have the advantage against Ditto. You send in a fast powerful sweeper and have the advantage against their bulky sweeper. You leave Ditto in and have the advantage against their fast powerful sweeper. Obviously it's more complicated than that but you get the idea.
Also, since the Ditto I posted can 4HKO itself with Struggle, you should run Relaxed with 252 Def and 4 Atk so you can always take 5 hits from any Ditto and will always win if you go second.
I agree fully with your first paragraph.
The problem with your nature +EV/IV spread however is that everyone will be using that particular spread, leaving it to luck which ditto comes out on top.
If Bulbapedia is correct (I highly doubt they already tested stuff like that in the actual b/w nds games), this means everyone will be running a ditto with a speed boosting nature (it's the only instance where it's nature actually matters anyway) and 252 speed EVS, making it a speed tie, so you will have 50% chance to be able to use transform (and by doing so getting 5 PPs) and 50% chance to fail your attack, so the chance to actually get one of the two ditto to struggle in this particular situation is at most 0.5^6 (you win the first speed tie and therefor get 5 tranform PPs, then you lose the next 5 speed ties).
You get the point, fights like this will be ridiculous.
EDIT: Actually it's more beneficial to run a speed hindering nature, anyway the chances to get it to struggle stay the same as explained above.
I think that the situation of ditto versus ditto in a situation where both are locked into non damaging moves only to struggle to death is so unlikely as to not be worth planning on, especially when it ultimately comes down to a coin toss.
If ditto is allowed into this metagame, you're going to need to run a counter to it outside of ditto. Crocune has already been mentioned. Are there water pokemon with access to self super effective moves and substitute? Those would be perfect to counter all forms of ditto, due to swimming goggle getting rid of the speed tie on non scarf versions, and substitute making the choice scarf irrelevant, assuming a ohko is possible.
Since Ditto takes its opponents' Speed, actually HP EVs are the only ones that matter - they're the only ones it doesn't take. So HP positive is all that matters insofar as nature is concerned.
All natures are the same with reguards to hp. And they're talking about ditto vs ditto situations I think
(with Illusion: idk if Zoroark gets a DW ability).
well, starmie is an easy one to think of...but I think you'll have quite a bit of trouble finding an opponent ditto that ISN'T scarfed. Most people won't want to take the risk of a speed tie.
All natures are the same with reguards to hp. And they're talking about ditto vs ditto situations I think
Competitively, Ditto will be about as useful as it has been in the past 4 generations. However, it is now the easiest Pokemon to train. Catch it. Fully Trained. No RNG abuse or EV training needed :)
I think that the situation of ditto versus ditto in a situation where both are locked into non damaging moves only to struggle to death is so unlikely as to not be worth planning on, especially when it ultimately comes down to a coin toss.
Yup it says so further down the page.That was in Generation 1. I can't help but assume that problem was addressed by now.
As someone pointed out, Ditto doesn't necessarily have lower HP than the original. Because its other stats are determined independently of its EVs, it can have max HP, beating some lower-HP sweepers that don't invest such as Lucario.Two things come to my mind when thinking about ditto.
1. Not all Pokemon carry moves super effective against themselves. This is admittedly more common in sweepers, but still - this doesn't aways help. Also, if eccentric works the same way transform did in previous generations (ie. it copies every stat except HP), ditto would have to OHKO the opponent in most situations, due to the enemy's base HP stat almost always being higher than 48 (... man, that's a pretty bad stat...)
2. Despite that, Ditto has very good scouting potential. All it has to do is survive a switch, and you know you're enemies entire set. I could potentially see having a Ditto with Leftover's specifically so that it could switch into versatile Pokemon and I'd know the entire set and be able to counter accordingly.
Anyway, just my two cents.
Ditto would be relying on its own IV's for Hidden Power, though. That's about the only anomaly I can think of.
So wait, I'm a little confused. Does Transform copy stat boosts like Swords Dance or not? (I'm working off the assumption that Eccentric works just like transform.)
Too obvious and easy for the opponent to avoid.
On another note, Ditto won't have to revenge kill if you can absorb a boosted hit with something holding an Escape Button.