RK3 is no joke boys. After seeing how smooth he looked in the pocket and how crisply he ran the offense, I'm feeling it must speak volumes about the coaches' confidence in Tommy that they are sticking with sending the redshirt freshman out there. We could have something really, really good in Armstrong.
RK3 is a game manager that knows the entire playbook. TA is still learning the full playbook so there is only so much he can do right now. But the difference is that TA has the "it" factor as a leader that TMart and RK3 don't have. He isn't as explosive running the ball as TMart is, but is pretty much better at everything else. He can give you more big plays than RK3, so that is why he is starting.
Armstrong is no where near as deadly of a runner as a 100% Martinez is. Martinez is the fastest QB I have ever seen at Nebraska, and is one of the primary leaders of this team, so I still do think he'll be a loss for us if he continues to be out this year. That being said, I agree with you that Armstrong is a more natural passer and has the ability to run a more balanced offense for us.
It is a very good thing to get TA field experience though.