>>33613084Actually the details on Ditto and its abilities are incredibly vague. The Pokedex constantly flip-flops between it being able to transform into "other lifeforms", "different shapes", and "whatever it sees", three totally different things. You also get this from RSE/ORAS:
>A Ditto rearranges its cell structure to transform itself. However, if it tries to change based on its memory, it will get details wrong.So based on all of this I can only assume the game doesn't let Ditto transform poorly, so it's only able to pull it off when looking directly at the enemy. For Substitute, imagine that the enemy is hiding directly behind it so Ditto can't see it directly. Doesn't make much sense for larger Pokemon but that's the only explanation.
