If you already seen the GT view, perhaps this means that you were missing something. Is it only the visual representation, or do you miss something else?

For the most part the missing part is the visual representation of the tree. However I did this little inspector because in the future I (maybe) will implement a tool for code rewriting like Rewrite Tool, but only the rule creation process will be done by manipulating visual representation of the ASTs.

 

Also, you can embed your view directly in GT.

That's cool and I know - seen it at Pharo Days :)