@Jasonsith: So, Ditto starts Transformed, then?
If that's true, then I suppose this comes down to:
1. How well does Ditto know Dan's techniques? Knowing it can perform them & doing so is one thing. Properly implementing them in an actual fight is another, especially against the creator of the style of martial art those techniques come from. Even if said creator (Namely, Dan.) may be a lackluster fighter, it's possible he may understand how better to use his techniques than Ditto.
2. The individual Ditto, & Dan. Quoting some of Ditto's Pokedex Entries, which will be in italics:
"Its transformation ability is perfect. However, if made to laugh, it can't maintain its disguise."
Is there anything Dan is likely to do that would make Ditto laugh? Aren't his specific ki attacks named off of/based on fart jokes? Doesn't he do a lot of silly taunting? Does he make humorous quips in battle? Is he humorously incompetent or clumsy? Would he pick up on it if Ditto being amused started to make its transformation "debstabilize" mid-fight?
"While it can transform into anything, each Ditto apparently has its own strengths and weaknesses when it comes to transformations."
3. I think this should be self-explanatory. Although, it may be irrelevant, since we can't quantify how skilled the Ditto is, & we may just be using the most skilled Ditto anyway.
"It transforms into whatever it sees. If the thing it's transforming into isn't right in front of it, Ditto relies on its memory—so sometimes it fails."
4. Supposing Ditto's transformation was undone, & it lost track of Dan somehow, this might be a problem, as it would have to resort to becoming an imperfect Dan, or other thing it's seen to transform into. We do know that, in-character Ditto will turn into a stone when asleep, to avoid being attacked, at least.
(For, a perhaps implausible example of why Ditto might lose track of Dan while detransformed, perhaps Dan runs in terror & hides upon seeing a duplicate of himself laugh & turn into a blob.)
Currently, I don't have a vote since I'm unsure how to consider those factors.