I think this is a great idea! As long as it's policed reasonably well, it should certainly speed up the initial learning curve.

Some form of cross-referencing between forums would be handy, e.g. Simple method to link from TS to ITT threads maybe?

Sounds like the new site could be compared to a public company forum: No technical jargon and language intended for the wider audience.

Two separate Wiki's sounds like a good idea too.

With regards to the risk of splitting the user base, I think the potential gains out way the risk. Worst case scenario, the majority migrate to the new one, the original one remains and becomes a forum for Uber Tableteers!