[META] Usability of Responsive Image in Core

Problem/Motivation

I am currently writing tutorials about how to use Drupal 8. While trying to explain things to newbie Drupal users, I found that IMage handling in Drupal 8 core seems odd and not that userfriendly in many situations.

Let say you install Drupal Core 8 from scratch. You have been advertised Drupal8 to be fully responsive from scratch but then you discover there are two modules images: Images and Responsive Images.

A/ Why needed two modules that from a naive user perceptive does the same (let you display images with nice formatter), but the second one better than the first one !?
Debate : from less naive user, you would say the first one let's you create some image styles that can be used in the responsive image settings. Here are possible solutions :
i.: Merge both modules
ii.: Rename Image to Image Style and let it be the module handling "the transformation and serving of images in Drupal". Rename Responsive Image to Image and let it be the module "define a responsive image field". Because actually well... Image have to be responsive nowadays. NOTE that if no breakpoints are sets, it could be easy to fall back to the behavior of Images here.

B/ Enable Responsive Image by default: Drupal is said to be responsive, let the image be too by default !!
Action:
1. enable Responsive Image module by default.
#1855412: Enable responsive_image.module by default for standard install profile →

C/ Create default configuration for Responsive Image module. Because when you enable it and you already have a working image field (per instance the default image field in article), your first move is to set this image field formatter to "responsive"... and get a weird error.


Actions:
1. Create default Responsive Image Style configuration
#2513604: Create default responsive image styles →

D/ Because there are no responsive image style set, I got a weird error here.
Actions:
1. Change the error message in the form (see above) for "I'm am the site administrator" !!
2. Change the general error message (see below): what am I supposed to do with this responsive image style link ? How about a more specific message ?

EDIT: wow, actually that links to this very same form... Hum.. that was so unclear then !
3. Add a link to Responsive Image style just as per the simple Image formatter (see below)

#2534074: Update error messages in field formatter when no Responsive Image Style available →

E/ Well... let's create a Responsive Image Style then. What is a fallback image ? Is that the default image style used by the field, like the one used by default for the largest display ? Is that the image style used for the lowest size: ie the image it fallback when on mobile ?
Action:
1. add a description meaningfull description to this option.
#2534066: Allow selecting the original image when creating a responsive image style →

F/ Then, before saving, I am requested for image style to use for each breakpoint. What is None ? A naive user would need to do the mental gym to find what is implied.
Action:
1. Rename option "None" to "Native image".
#2534066: Allow selecting the original image when creating a responsive image style →

Proposed resolution

See above

Remaining tasks

- debate each point if needed
- implement the sub-issues listed above.

User interface changes

- yes: that is the point

API changes

Point A would lead to a lot of disruptive changes, thus to be debated

Data model changes

Point A would lead to a lot of disruptive changes, thus to be debated