Hi Nikhil,
Happy Holidays! Yeah, I've actually been thinking about this one for awile. I spoke with the product manager for Web Parts and he said, as you mentioned, in theory, it gets tricky managing server-side values with the client/parent window relationship, but he also said it's not too far fetched to work something out for a later build.
I think this would be really helpful, and would inevitably come up. I think WevParts are great, I just don't care for being limited to having to work within the same screen my Web Parts are on, especially in cases where my real estate is limited.
Keep up the good work, and thanks for listening!
Jas