-> Peach can overcome her killing potential:
Donkey Kong doesn't need to overcome such issues, he's a killing machine. Donkey Kong is better here.
-> Peach is better at spacing
With Donkey Kong having better range, better aerial mobility, a REAL mid air jump, down b to completely zone the ground, and bair covering most aerial approaches, it is hard for Peach to argue that she has superior spacing ability or "up close" ability. Especially with DK's amazingly fast dtilt with it's high tripping chance, and fast and mostly safe ftilt for a 'gtfo'.
It is hard for me to see anything Dark Peach has said that can over come these qualities.
-> No one in the SBR knows Peach
I bet you there's barely, if any, real DK mains in the SBR as well; whilst there is Edrees (I believe) and Sky in the SBR... I guess these people dont know Peach; I guess these people dont know Peach well enough to have at least Sky agree DK is better.
But people can see that as a character, where DK is made solo unviable, in a similar way as Peach (you can show match ups all day, get both sides to agree... Marth, MK, Snake, HAI!); DK is the better character.
-> What about Pit!?
Better recovery, better killing potential, similar damage potential, slightly weaker spacing ability, no characters out to make him 'really' unviable, MUCH BETTER camping potential (++ IN BRAWL METGAMEZ).
This is the perspective of the current view of the metagame in my eyes; you saying otherwise holds little when there is no definitive tournament or otherwise information to back it [Peach] up.