Your feedback is highly appreciated and will be taken as constructive criticism.
The main reason to begin the visual designer project was that the classic approach had come to the limits of its extension capabilities and there was no way to satisfy the new needs of our clients. You are probably right that some of the designer areas are not 100% covered yet and may look unfinished or not polished enough. However, we believe that the designer has already covered most of the functionality provided by the classic wizards, which was actually the main target we were aiming at the last year. Since the Q3 release, our main goal is to improve the weak areas of the product and not to introduce so many new features.
Regarding the usability problems you mentioned, they could be caused by the big difference between the classic and the new visual approach. If you have already used to the old wizards, it could be a bit frustrating to start using the product the new way. If you do not want to invest time in learning how to work with the designer, you can still use the old wizards if they work for you, we have no plans to get them out of the product any time soon. Nevertheless, you are encouraged to send us any feedback regarding the experience you have with the product, your suggestions will surely be taken into account. Maybe at some point you will reconsider switching to the designer, once you see that it is mature enough to suit the needs of your projects.
Now let me answer your technical questions.
At the moment it is not possible to have in the designer an association with only one end but this will be supported at some stage. We will remove the misleading information from the documentation until this happens.
1) This indeed turned out to be a problem with the initialization of the type converters used for converting CLR types to SQL types and vice versa. Closing and opening the newly added rlinq file should avoid this behavior until we fix the actual problem.
2) The EntityDiagrams class is actually the context class of your domain model. It contains an IQueryable<T> endpoint for each persistent class in the model which you can use for linq queries. Methods for Adding and Deleting objects are also available. Another difference to the IObjectScope is that transactions are handled automatically and you need to call only SaveChanges() or ClearChanges() to commit/rollback the transaction.
3) The dependent option corresponds to the "cascading delete" option from the old wizards. If enabled, the collections of referenced objects are deleted from the database together with their parent object.
The managed option is not a new one either. When it is enabled the two ends of an association are kept in sync automatically and setting the reference on one of the association ends is enough. The other will be updated by OpenAccess. This option has been added recently to the designer but you are right that the documentation is not updated yet. I will make sure this is fixed soon.
Again, thank you for your feedback and do not hesitate to share with us any other thoughts about our products.
the Telerik team