I am just wary about adding more layers if there aren't strong reasons for it. On the other hand, it can well be that it scales in the end. So, we can experiment but we should be careful to trace the effects :)
I am just looking for ways to simplify Mondrian. The VW version of Mondrian was complex. We have simplified it over the years. But it remains complex.
It is great to want to simplify a design, but this would only happen if you introduce some extra concepts (like a Graph). However, this comes at a price, but maybe it is worth it.
Not only. For example, I am not convinced about the class MOBrowser. Maybe the Easel should be an independent project on which Mondrian would depend on.
Regarding VW vs Pharo, I do not see where the Pharo version is less complex than the VW version. In fact, with the caching it is slightly more complex.
When I said, I was referring to small things, such as having shorted methods and smaller classes. A few months I made the core of mondrian completely independent from other packages.
Cheers, Alexandre