Agree with you. I would like to have more choices how to build my own custom weapon.But not with schematics.
Let me explain.:You search the wastes, and find various junk from cars, weapons etc. You have 1 dedicated weapons making machine, and when you click on it, you get interface in which you can drag and drop parts in realtime(and combine it.). Something similar with "The incredible machine". The sucess of combining the parts, and weapons damage would be based on your repair skill. Sounds good eh?:)
