I think it will be a good trainer. We have some really fun 30-35mph mountain roads around here. I was running 44mph in 3rd most of the time and it was a riot. I usually do it on a 2008 250 Ninja, but I sold it to put the money in my 300 Ninja fund, the next day my buddy that owns the Honda shop sends me a text: "your GROM is here" , there went the 300 Ninja Fund.
The bike is hilarious. In my school I put a lot of emphasis on the importance of deliberate precise actions for new riders (I won't get into the rationale here) and this bike is excellent giving at feedback about your inputs. A light touch, head and eyes up and it flows perfectly. I feel the tires are a little harsh on little ripples in the pavement, they will probably need to be replaced.
I'm a little concerned about how it will behave at the hands of a newby in some of the more dynamic exercises, like stopping quickly in a curve and maybe swerving. I'm going to go hammer it and do some stupid stuff to see how it responds wearing full leathers just in case. Ridden back to back with my other training bikes shows just how nimble it is. I'm hoping that it will be perceived as not intimidating and give the less brave students a sense of confidence.
So far, the bike is exactly what I expected, if not a little peppier than anticipated.