but i think it is important that we separate between visual properties and functional behaviour. for an example, the iemguis store a lot of gui-information in a long long list of arguments. i think this is bad style, but it is not thomas' fault as this is the way how it works: one object is entirely representated by one message. the problem with this is that you cannot expand it (just have a look at the evolution of the arguments of the iemgui's)
I'm personally using flext attributes with great success. It uses the Max/Jitter style of @arguments, which allows easy structuring of creation arguments. Flext also has a built-in editor for that (context menu "properties")
best greetings, Thomas