Do you have plan to add a DSL Designer to the framework for Business Entity Modellling and relational code generation ?

Or any other way to improve this requirements ?

To a degree, yes.  But we never plan to be a full-tilt code generator.  We will create a few inline DSL dialogs (not a custom language) but rather just an extension of VB.NET or C#.  Unlike some of our competitors, we never plan to have a unique "SF language" which defeats the purpose of a framework and being able to program in the language of choice.

However, we will create some custom tools through the DSL tools in the next major version of SF to help build the BOs as well as some additional RAD tools as well.

Thanks for the good news.

What is the timing for the next major release ?

Nearly ?

As you have noticed, we are still waiting to release the 1.6.6 build which has over 200 enhancements, fixes, etc. since the 1.6.5 release.  So all of our releases are pretty "major."  In regards to when we will implement new DSL functionality, I cannot say exactly.  I know that it won't happen until 2009, but that is about all I can tell you at the moment.