Hi DW,
We are happily using forms for editors, however we feel like HTML5 is not really supported at the current stage.
The problem occours because there are no way to set the type attribute on text fields, this prevents mobiles from opening up the correct keyboard and besides many javascript validation plugins works out of the box using the type attribute.
Currently we can create the fields shown in fields.png. My suggestion is to allow editors to enter a type attribute in the Text field dialog (see TextField.png) or add HTML5 types in some other way.
Thanks