In the 'code view', you would have something very similar to the script editor that is already in GM, but the code structure would look a little different to reflect the change. Now, I am unsure to what extent the language is getting overhauled, but depending on the scope of the changes, this code view could provide benefits ranging from a more familiar environment to programmers coming from other languages to the facilities that would be really necessary for an object oriented language. 'Design view' would then simply be essentially what the Object form is right now, with whatever necessary tweaks will already be coming with the language overhaul.
If only the syntax of the language is getting cleaned up, then this could simply allow the user to define a class with a name matching the object name, and override methods which match event names. I feel even this would be very useful, because if you need to add a variable while coding some functionality in the step event, you'd need only to scroll up a bit to the create event, instead of closing the editor, click the event, and reopening the create event, etc. While this might seem like a relatively petty thing to want to change, it will very likely affect how seriously a lot of developers coming from other languages view Game Maker.
On the other hand, if the language is getting some more advanced features (such as things along the lines of more OO concepts, like associating methods with objects, instead of scripts the way they are now), then this would clearly have the benefit of a very natural way of defining the method within the class. But more than that, if the default features that every Object in Game Maker currently has were put inside a class called GMObject or something similar, then each class the user defines would have a natural way of deciding whether or not to include that functionality in their object. This would allow for the 'cheap' objects asked for in this thread.
Well, what do you think? And do keep in mind, this is for discussing the addition of the code view functionality, not GML language features in general. That said, I would looooooooove for things to work in a more OO fashion, with methods, private/protected variables, polymorphism, etc. (especially because these features would allow for and encourage better design patterns in Game Maker in general; all public data is not what you would call professional )
And lastly, as I see it, the pros and cons of making these changes to Game Maker.
Pros: Improved workflow; more attractive to experience developers; allows GM to be easier to pick up coming from another language; can be implemented regardless of changes to language.
Cons: More work on GM Development team; if few changes are made to GML during the overhaul, could be seen as unnecessary.
And here are some mockups to basically convey the idea.