Hypercard could be reworked without the drag and drop, double tap or long press pops up a menu, select what you need from the menu. It would work like every other phone app and leverage the other apps which come stock, want to place a picture than double tap to get the menu, click add image and it opens your gallery app and lets you select a picture and do basic editing, click done and the image is placed. And I can think of dozens of ways to extend the hypercard idea based off what a smartphone offers.