Can you, please, describe, why do you think that Genera was superior to Smalltalk? I never had the opportunity to test it for real; however, I checked a lot of materials about Genera, and my impressions were the opposite. So I would really appreciate some arguments.
You should really try and use it if you are seriously interested in this paradigm. You can get your hands on it with a bit of searching. As for comparing the two, the philosophies and ideas are similar. Obviously there was significant cross-pollination.
Smalltalk always had an experimental, research-oriented aura around it. It did end up in industry but in a degraded, business sense did not live up to its potential at all in that domain. The Smalltalk environments that have significant value today (mainly Squeak and to a somewhat lesser extent Pharo) are firmly rooted in research.
Genera embraces the same philosophies but also hones them to an extreme degree through the forge of practicality. Its systemic cohesion and attention to detail is unparalleled. There is little "slack" and you don't get the sense that there exist systemic aspects that were not extremely well thought-out in both design and implementation.
