Good introductory article, Paul. But regarding:
the power and the flexibility of our rule engine allows us to quickly develop the business logic
Rules Engine summaries make lots of use of pitches like that. Trouble is the "us" part. Who's "us"? I just can't see a business user using a tool to write business rules, clicking save, and having the changes go live into production. I think it's much "easier" for biz users to fire up MS-Outlook, write up the rule and send it to an IT manager/developer.
You mention tools, but in my experience, even if the tool makes writing biz rules easiER, business analysts will still prefer the outlook/email way. To them, *THAT* is just as easy as it gets (or phone, or conversation in a meeting).
My fear is that rules engines will become another ball and chain for developers. Write rules in an XML file. Deploy into container (the rete engine) to run to see if it 'works'. To make life easier, developers will be using the tool that the biz users were supposed to.
Just my $0.02.