Thanks all - a little more clarification.
My designer says that creative responsive templates will interfere with the editor, so I'll lose some ease of use if I really want to proceed. Have you found this to be true?
Here's what she wrote:
Responsive templates will interfere with the editor, so I'm not sure you want to do that. You need to talk with your Marketo rep to confirm but that was my understanding of things in talking with Glen. Being able to use the editor is a trade-off for having a responsive template was how I understood things. I think you'd really need to understand how this would affect your use/ease of the editor before moving forward. If you want me to be on the call with you I can do that, just let me know.