I recently moved from many years working with Eloqua to a new Marketo implementation and really struggled with the new Marketo Design Studio 2.0. I initially had our designer build a couple of complete templates with placeholder (latin) text with all the CSS, a form, etc that I figured I could then simply apply and then edit with specific content. Turns out you can't edit anything that's on a template, you can only place new elements on it. So after much trial and error I finally ended up with a set of simple templates that are essentially frameworks with headers, colors, footer and CSS that I lay content elements on to, including a form. Then working from those new templates I then built a few reusable LPs that I clone which then enables us to edit content since that content was placed using the designer. I also am able to change the form based on campaign needs. So if you want to be able to edit your own LPs this is the approach I found that works.