As I read what you have to say and consider it, I'm struck by a thought regarding originality and the Indian line. I don't believe that Polaris intended to do anything original with the Indian. In fact, I am recalling a vague thought I had at the time that the Thunderstroke engine was announced. That was, why would they put so much engineering and effort into designing an old and not so efficient engine design? Considering what it is, they didn't do a bad job of producing an engine with good torque, but it seemed like a step backwards considering what had been achieved with Victory.
But, on consideration Polaris put themselves into exactly the same type of trap that Harley was in for quite a time. Modernization of engines was not going to sell to "the faithful". For whatever reason that I may never understand, there are more riders out there (excluding the rocket crew) who want antiquated motor design over optimal design. See V rod. So, Polaris started from the premise that they needed the old OH valve, push rod motor to sell to the "faithful". Now, that sales are up(?) I guess it's time to ease in the (repurposed Victory) upgrades. Maybe it will work?