I'm not aware how much, or how easily or hard drawing tools are to integrate in a web based platform. But supposing there is the possibility of integrating this easily, or without much trouble, something that could help a lot it's if the drawing tool would have scissors smart selection alike capabilities, like many desktop softwares have like GIMP. In GIMP, when you select a shape with the scissors, the scissors smartly correct the mistakes you make when making the selection. In this tool, making mistakes in the selection is easy, and they lead to black areas/ spots in the 3d figures, which at least for newbies of 3D are hard to remove in Blender or other 3d softwares (and this tool with others is getting special attention among newbies of 3D)
I'm not aware how much, or how easily or hard drawing tools are to integrate in a web based platform. But supposing there is the possibility of integrating this easily, or without much trouble, something that could help a lot it's if the drawing tool would have scissors smart selection alike capabilities, like many desktop softwares have like GIMP. In GIMP, when you select a shape with the scissors, the scissors smartly correct the mistakes you make when making the selection. In this tool, making mistakes in the selection is easy, and they lead to black areas/ spots in the 3d figures, which at least for newbies of 3D are hard to remove in Blender or other 3d softwares (and this tool with others is getting special attention among newbies of 3D)