After some testing I have found that Forms 2.0 with a Text Area field will not display in IE 10 or 11. With just normal Text Field Types, the form displays, but once you add a Text Area field type, the form disappears. Forms with Text Area field types utilizing the original (not 2.0) form builder seem to work fine in IE.
I am not sure why this happens, but I believe it is a bug that Marketo needs to fix.