The Roman Catholic Church is important but no more important than the Mafia who they teamed up with to bankrupt Italy in the Gelli affair.
That seems pretty unlikely to me, Robert. The Catholic Church currently has 1.25 billion members, and The Economist estimates their annual income at $170 billion.
http://www.economist.com/node/21560536
Whereas like any secret criminal society, the Mafia (that is, the Sicilian Mafia aka the Cosa Nostra and its affiliates) has a relatively tiny, secret membership whose power and reach is difficult to estimate, but Wiki thinks their annual revenue is about 6.5 billion euro in Italy.
https://en.wikipedia.org/wiki/Sicilian_Mafia#Current_status
So based on these figures, one would need to guess that the Catholic Church has far greater influence than the Mafia; as well as being a far more respectable and highly esteemed organization.
Moreover, there have been long-standing accusations that the Roman Catholic Church and the Mafia are deeply linked; as the Catholic Church, of course, will not openly acknowledge. See, for example:
http://www.nytimes.com/2003/06/22/weekinreview/the-basics-church-mafia-why-the-link.html
Now, in response to your questions about Saussy:
1. He does not discuss Thomas Aquinas, nor does he mention alchemy.
2. He does not discuss Malachi Martin.
3. He has a chapter entitled 'Medici Learning' in which he discusses Clement VII, but does not mention the Borgias.
4. He does not mention the Corpus Hermeticum or other hermetical works.
5. He does not discuss double and triple agents, nor does he identify any.
6. He does not mention the Westphalian Treaty.
7. He does mention the Rothschilds and their role as Vatican bankers, but does not mention that any Vatican bankers were responsible for assassinating any Popes.
I'm not sure what you're driving at with your questions. Saussy's book is focused and coherent, and generally tries to support its claims with detailed research; accordingly, it is hardly a fault that he doesn't cover every imaginable topic.