Good for him to get some seat time one the 04 Ducati. It also shows that Ducati is strongly committed to solving their problems. Nothing can substitute for testing miles.
Ruben indeed is spectacular to watch and very much has the needed "attitude" for racing. Given a competitive bikes, I agree that he would be running at the sharp end of things. The 6 lap "club race" last Sunday showed that he has what it takes. Yes, he may crash now and then (far less than he used to a couple fo years ago), but as they say: If you're not crashing, not you're not trying hard enough. (At least, this has always worked for me.
)
I vividely remember running into him at Laguna Seca last year, as he was about to enter his pit garage just before the second race of the day. Because he crashed out of the lead in the first race, I said to him "stay on it this time!" He walked a couple more steps, then turned around, looked at me, and simply gave me the finger.
He promptly won the second race! Pure class!
I've met him since and he is a top guy. Best of luck to him.