Simulating TYPO3-Template-Engine For my next drupal project I need more flexibility in content-styling, than the standard approach allows. I need to be able to build the content-body for every single node from different elements. Like in TYPO3 I need a sandbox of pre-styled elements (e.g. full screen image, two column text, 3 boxes side by side, etc) and be able du add as many different elements as I want. The markup and styles should be saved in my theme, so there should not be any html in the content fields.

e.g. 

EDIT 1: Its basicly something like the Form builder what I am searching for. (see comments)

Usualy I have used an WYSIWYG editor whith shortcodes, insert module and predefined styles, but I learned that it is not a good practice.

My approach which atm only work in the theory:


I use Field collection module for being able to add unlimited blocks of the collection. 
Whithin the field collection I have one select-box where I define the template_name for the collection.
Than I add all the fields I need (e.g. text, image, backgroundimage, date) to the collection
With the Conditional Fields module I controll which fields are needed/shown for every single template (see select box).

Screenshot 1 // 
Screenshot 2
The theming is done in my field-collection-template file (if template_name == x, render this whithin  particular markup)   


Unfortunately this is really complicated  ( I have to make a dependies for every single field in any template).

is there any better solution?
What about using entity references. You mention the field-collection approach, which has the same overhead as using entity references.

Basically you create a few node types that each conform to a different block element that you require. Then you create a master node with an entity reference field and select all of your block element node types as candidates, and set the filed count to unlimited. Then also use the inline entity form.

This will work but has a heavy server load.