My Drupal 8 modules
The carousel image formater uses the template of the Boostrap theme to display a carousel. Nothing particular in this module I only got a small difficulty to get the attributes of the picture (title and alt) without loading it.
Developping with Drupal 8 feedback
Here is my feedback for developping these first Drupal 8 modules to use in production:
The new render pipeline uses the Render API of Drupal as global, all that go out in associative array with the famous Drupal recognizable key prefix # becomes the markup (most often html). You don't need to use any render or drupal_render functions outside of render context.
Twig is rather flexible, it is really a big progress. Facing PHPTemplate you probably always need to add a preprocess function for every code processing you need, even the small ones.
You probably had to deal with a lot of preprocess functions, and in the end get some difficulties with overrides.
To put your environment in developpement state, without any cache, is however a bit tricky, configuration of twig and Drupal is at two different places: see explanation.
Fortunately a new tool, the Drupal console inspired by the symfony console allows to get this faster.
I would come back on this
substitute companion of Drush.
Features in core ! What a great progress, this is one of the modules that changes my development workflow when I started using it.
Feedback on Drupal 8
Integration of ckeditor and quick edit is a good point, but it is far from making of Drupal an user-friendly CMS as Wordpress for example.
Multilanguage on Drupal 8 is based on entity translation, fields are translated and there are no more nodes relations like in Drupal 7. It is a big improvement even if everything is not although perfect, you will probably get some troubles with url aliases.
A translation dashboard is missing, there is a work in progress with Translation Management Tool but it is not currently ready for production.
For the negative part there is a flagrant lack of some modules, for example pathauto! A lot of other modules in dev version will crash your Drupal... and others are very "lightened", which can be very frustrating, for example VBO without the mass modification of entities fields values.
Drupal 8 ready for production?
At last I think it is even too early for a big website in production with Drupal 8, even less with Commerce which seems however soon ready.
Drupal 8 is rather ready for an headless website, the Web services part is very efficient, quick to set up with an easy modelling part using Drupal entities concept.
Drupal 8 is a final product?
A rather good point is the documentation, it can be sometimes incomplete but it covers already almost all aspects of Drupal 8, and you can find a lot of useful articles on the web.
At the moment you come out again really frustrated by an experience with Drupal 8, there is a lot of great improvements facing Drupal 7 but you will always find yourselves a bit frustrated. Modules which are now in the core are too lightened and need complementary modules, sometimes it's even missing the UI part!
Every progress seems not to have been far enough and the integration of big modules in the core brings the need of more new complementary modules... You will need to assess the situation with Drupal 8.1 or 8.2 which are full of promises.