You're such an optimist EP
I have no idea what Naquin can to long term, but you don't either. Recent Reds who've won spots with production...
Adam Duvall - in 2016, the Reds traded Mike Leake to the Giants for the projected 4th/ 5th outfielder and he responded with 33 home runs, 101 RBI and a spot in the all star game. Followed that up with a good 2017 season, although his numbers really tailed off after the all star break, I think he injured himself in the home run derby.
Scooter Gennett - Scooter came into the 2017 season as a spring training invitee and potential utility man, he hit so well the first month of the season the Reds made him their permanent 2nd baseman, over Jose Peraza. Gennett easily had the two best season's of his career in '17 and '18.