Form Builder in Core to provide Schema, Form & Display fields edit forms

the following proposal came to my head while just watching the great drupalcon london session
AN INTRODUCTION TO FORM BUILDER - A NEW INTERFACE FOR FIELDS
http://london2011.drupal.org/conference/sessions/introduction-form-build...

when talking about "form builder in core" and the "potential for fields" around 40min of the presentation, actually i liked option 2 better :)
i just wanted to propose instead of having form & display, introducing 3 "stages": schema, form, display.

it's just a very raw idea, but well i think being able to chip in at wherever stage of the 3 would be very valueable:
- schema: add datatypes like text, integer, ...
- form: add form widgets like textfield, textarea, data selector, ...
- display: add formatters like plain, imagecache presets and so on

some additional notes:

of course, the same form or display option might apply for different datatypes. form example: textfield for text & integer; display example: plain for different datatypes. so we might need to list all of those combinations in the right-hand-side palette while highlighting the most reasonable defaults / hiding advanced use case combinations.

while schema definition is unique, there can actually be multiple forms & displays on top of the schema definition (a views-like master + specific displays approach might be feasable here).