While designing this feature, I ran into the 'doing it visual is cool but unproductive'-wall: my plans were to create designers with a custom language in where you could define rules etc. but it would be more time consuming to type these in /design them there, than when you would type them in in code in vs.net.
So I stopped with the visual approach and invested a lot of time to get a validation framework implemented in v2 which allows you to add the validation code to either validation classes or to the entities without a lot of effort (read: just write the validation code, and you're done). This seems to me the most productive way of writing validation code.
