I just watched the video for the new repeatable fields and this seems to be one of the last features that were missing. It is great! First I thought it would solve the problem I am about to describe, but then noticed that it wouldn't.
I am currently building a page for myself and want to have a modular layout. I don't want a classic layout with a body, a sidebar and a definite number of editable fields per template. What I want to achieve in the content of my page are floatig (inline-blocking, to be accurate) columns which can be added more dynamically. For example, I could have the following "blocks" to build my page's body:
A = A column which has a width of 20em
B = One with a width of 42.5 em
C = One with a width of 65 em
D = One with a width of 65 em and a dark background
So let's say I want three pages where content is supposed to be arranged like this:
A A A A B__ C____ A A A D____ B___A A A A B___A A A A A A A
The normal way would be creating four fields (A, B, C, D) and three templates where these fields are placed in the order described above. The problem is that if I wanted to create a fourth layout, I would have to create a fourth template. As you can see, there is a quite large number of possible combinations. What I want to achieve is the liberty to add new layouts and rearrange content independently of the code out of a set of blocks. Think of it like a letterpress where you can exchange individual characters and rearrange them as you like.
At the moment I am creating each block as a child of the page where it should be placed and assign css classes based on the template name (for example, echo <div class="$templatename">$page->body</div> for each child) Unfortunately, that means that the individual parts of a page appear as individual Processwire pages and clutter the site tree. While this approach is useable, it is not very elegant and abuses the pages for lower-level objects which are not meant to be accessed single pages.
Now this is a feature suggestion and I am feeling bad for it because I value all the hard work that has gone into this great CMS. This is what I was thinking about:
How about allowing users not only to add but to create sub-pages to a page while editing it. Much like the repeating fields which create pages in the background and add a page with the same template over and over again, one could chose from a previously set range of templates (like the template limitation for child pages: allow template-a, template-b and template-c to be added as fields to this template). So one could still render all sub-pages through the markup but would only have to add a new field and some CSS if he wanted to have a field E, which might be a 20em wide column with pink background and bright green text in Comic Sans.
I hope what I wrote made sense to you and would be very happy if someone suggested a workaround that already exists and that I completely missed until now.