I don't think there's need to have Jon's guitar part in Runaway at all. In 80s they played with one guitar and the performance was much better. I think it's because of the keyboards - they were huge back in 80s now it's thin (nice word you used ) I was watching Runaway from each decade carefully and found out that in 80s David played the main melody with both hands, now he use only the right one!!

Back to topic - I do not hear Jon's guitar parts very often. On the other hands - Sleep in Amsterdam 2005 sounded weeker with only Richie playing.
And what about the vocals - I always have feeling that mics of all the band members are turned down compared to Jon's.