What makes Edit-and-Continue difficult/impossible for Silverlight? What's the next-best thing?

NOTE: related question from ~2 years ago just confirmed SL3 couldn't do it.

Since Silverlight 5 will (AFAICT) still not have edit-and-continue support (even for out-of-browser, again AFAICT), I wanted to ask if anyone knew what made it such a difficult thing to get working for Silverlight? I'd be happy if it was even restricted to a particular scenario (IE10 on Win7+, 32-bit Silverlight 5 only, for instance), because at least then I could develop against that much more quickly/productively and then have the other platforms for testing/verification once it was working fine in the one scenario.

I've wondered what scenarios would be closest but have working edit-and-continue. The only thing that jumps out at me is creating a WPF app that lives in the same solution (perhaps using Prism 4 since it has the goal of minimizing needed changes between WPF and Silverlight app) and developing them 'together', being able to use EnC for the WPF app and then hopefully only needing to do minor development in Silverlight.

That's a lot more trouble than I'd like to go through, though, and I wonder what else might work? For instance, .NET 4 can load/use Silverlight 4 assemblies, and WPF can host (IIRC) Silverlight, so could I make a WPF 'shell' that actually ran my real Silverlight app (just hosted within the WPF app, itself开发者_StackOverflow中文版 running in a .NET 4 CLR).

However, such efforts are shooting in the dark (at best) without at least some basic understanding of what it is about the current Silverlight CLR/runtime/whatever that makes it difficult to have EnC in the first place. Knowing that might hopefully help in directing to more viable (less hassle) workarounds, at least in theory. :)

NOTE: answers that only work in certain situations (as stated above, like IE10+Win8+SL5) are still great to know about - I'd rather have the feature some of the time than never! :)

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Next best thing is edit and recompile. I've been using it for awhile and it works pretty well.