Actually it wouldn't be difficult to add similar view protocols to Python objects as well (I used GT extensively a couple years ago). Pretty much everything is possible, but the live debugger and driller would be really difficult to replicate, which is where GT really shines for me. Alas it was just too much to properly bridge it with Python, where the majority of my work lies, and GT becomes overwhelmed when passed a fraction of data Python handles with ease.
Simple views sure, but tools like the driller or debugger are great examples of what I'm trying to highlight about when I say having the views work over actual objects is really important.
Because if it wasn't for the fact the graphical stack was implemented as smalltalk objects, you couldn't build tools like the driller or debugger since they would have to be implemented as a secondary piece of software that loses the original context.
Like for example, I built a custom tool for myself when I was working on this p2p network and had a section of the codebase with some non obvious control flow, since it was handling multiple different p2p networks at the same time. Normally this is where you include a diagram in the docs, but in about an hour I built a custom code editor for the class, that visualized all the control flow and explained the cases in a flow diagram by simply introspecting on the methods defined in the class. And this tool never fell out of sync like a static diagram, since it wasn't hardcoded by me. And from that point on, I worked within this tool whenever hanlding anything related to this.
And fwiw, the python story is pretty seamless from my usage of it a few months ago. I was able to integrate and use python libraries into this project without much hassle.
Over the last couple of years we added a reasonably extensive infrastructure for working with Python from within GT. You can define contextual inspector views both in GT and in Python for live Python objects, for example. There is also a debugger for Python.
Also, GT is now also a distributed Smalltalk system, too. We use it in productive settings to compute large jobs on large data sets :)
