I devoured that interview - great thanks, George!
Even as someone well-acquainted with Rainbow, I had no idea he played such a role in the first non-touring line up. Certainly, that debut Rainbow album has the most musical groove to it as regards rhythm section and keyboards, possibly because you yanks just play with a more relaxed feel than European musicians. In contrast, I thought Rainbow Rising a one trick pony album and detested its mix which let Bain's bass hardly be heard (at least the European mix did, there is also a better US mix out there). But then I never really liked Powell's robotic drumming either.