I actually think Dreamworksland is a vastly superior family-oriented land to SNW.

It is not anywhere near as flashy, but it's
very functional. Two shows, a kiddy coaster, five easy-to-access M&G spaces (including the really visually appealing Shrek spot, and make it six spots if you count meeting Spongebob next door), an interactive game, and a significant number of play areas of different themes, including both dry and splashpad / bucket elements.
The key element with those latter offerings is that they are specifically made and designed for kids. Nintendo has essentially
nothing like that.
No upcharge elements necessary either. (Remember, you need to pay at least $50 to unlock access to the poorly designed play spaces in SNW.)
Flats and a dark ride would absolutely improve Dreamworksland, but I honestly believe SNW would've been far worse at improving the parks' family offerings than what we actually got.