Considering he referred in the stream he wanted to introduce new "gimmicks", and 6 new characters will be done in two years, unlike this season pass, I think he will push to a more complex gimmicks in terms of gameplay or the character itself, like Ice Climbers or Pokemon Trainer. (that or the DLC team has been reduced).
In any other situation I think it would be a good sign for Isaac (because he could have a lot of options, since Djinn management to a earthbender who could manipulate the stage/create some terrain), but knowing who is choosing Dlcs and seeing he's really close with a lot of his picks, I really doubt we get an opportunity :/