Well Those are all good points but a heavily platformed stage isnt going to help fox with 1) camping because you have to be on an equal leveled platform which dk can avoid if he stays below you specifically on the bottom level, 2) It limits fox's speed. Now dont get me wrong, fox can still be quick like uzi showed us in the vid but not having a solid stage to run on limits fox's ability to place himself on the stage.
I'm not saying that this is a bad stage for fox by any means, i just feel that its a better stage for DK. Considering that 1) its harder to gimp him with shines or whatever because of all the ledges to grab onto 2) smaller platforms to have closer combat on (which is something that DK is good at) 3) low platforms that DK can attack through while standing on the platform below (utilt, usmash, dsmash) and 4) the fact that fox WILL HAVE TO BE IN THE AIR leaves him open for many many uairs from dk which just seems to own. [edit] also DK's ground pound attacks below the platform too.
Now its not a win all, fox has some Good things goin for him. Like nair crossups and JJC. Also if Fox manages to get under DK in the air its pretty much an extra 50% damage. Fair to falling uair is amazing and can kill decently early. Also as a situational tactic fox's usmash will connect from under the platform if DK is crouched (not likely) or if he is landing (a lil more likely). But even from the top usmash doesnt kill till 96 w/ good DI from the top platform (just something to keep in mind about DK) [also utilt can connect in the same manner but the placing has to be perfect]. And Uair ***** too :]
So yeah, I can see the argument but i feel that DK would have the upper hand here. But it would still be a risky counterpick for both imo.