You can run any smalltalk code from workspace-style frames in the Inspector, Workspace, Explorer, Finder and Debugger. You can edit classes and methods in these windows, as well as spawn Browsers as desired. I'm not sure what the integration points are that are lacking. That's not to say there can't be a better way, but I cannot see the point he is making.

I couldn’t discern a point either. Having been a smalltalk programmer the only thing I really miss is the exceptions and the way they could be intercepted and a value injected back into the execution flow.

I’m sure we could code up a class browser for any language that offers introspection like C# but I don’t see the point any more when programming has reverted to functional styles or chunks of lambda expressions.