Here's a "wishlist" of features I'd like in such a framework:
- Absolutely no boilerplate code: It should feel more like a powerful templating language than a general purpose programming language.
- A static type system that's checked before your application can go live
- Vertical integration, especially towards the database: You could go really crazy with this. LINQ-style query-ability is just the beginning. Imagine if you had a typed access control framework that lets you specify which users/roles can access a database column. Or built-in ways to handle migration and automatic schema checks to prevent mismatch issues.
- Useful primitives, especially around authentication and authorization: For something simple I should only have to write my business logic.
- FFI (for example to C or JVM libraries)
- Automatic and safe dependency updates