I started creating my game using XML with XNAs IntermediateSerializer and after a while I started a LevelEditor. I quickly published a testing version and noticed that the XNA redistributable doesn't contain the IntermediateSerializer.

If this is true, then that means that I have to use XMLSerializer and recreate IntermediateSerializers behavior. OR... Redistribute Visual Studio Express + XNA Redistributable to each Level Designer.

What do you recommend? How hard is it to change my current architecture using XMLSerializer OR how bad of an idea is to make people install Visual Studio? Is there another option?

Thank you.

You would probably be in violation of the XNA Game Studio license agreement if you attempted to re-distribute the content pipeline assemblies. You simply cannot do it. Instead, you'd have to point people to the public download, and tell them to install it (which, in turn, means they have to install Visual C# Express).

If you don't want to do that, you have to move to a mechanism that doesn't use the content pipeline.