I would personally love to see grid-interchangable items. However there's a hitch: Inworldz is now developing new, powerful scripting functions that don't work elsewhere. As well... OpenSim has developed new, powerful scripting functions that don't work on Inworldz. So even if items could be ported securely and safely and with owner's right intact... you'd have an item that just sits there with script errors popping out all over.
As was mentioned by Inworldz devs... at what point do we stop progressing for the sake of "compatibility"? If they try to retain compatibility with OpenSim, their own progress ceases. They're not willing to do that... nor should they be.
I thinks that the idea everyone must be compatible and interchangeable is a utopian fairy tale. Inworldz is not OpenSim. Avination is not Inworldz. None of us wants to be Second Life.
The fact that these worlds bear a functional resemblance tends to make us feel they should be interchangeable and compatable and all going for the same goal. That is a dillusion. Most automobiles have an engine and four wheels. But try to interchange parts and one quickly finds out how different they really are.
That's the simple reality of VR these days-- and I think people need to recognize that reality and just get on with their grid of choice. : )
Some people prefer Ford. Some people prefer Chevy. Some people prefer Toyotas. No one expects them to have interchangeable parts.