Hoping that pitchers dramatically improve is simply a recipe for disaster.
Harang, Cueto and Arroyo have been circa 5 ERA pitchers this year. Owings has been just under a 6 ERA pitcher this year. Anyone who expects this to suddenly turn around is just hoping.
One of them may do much better. But another may do much worse. You cannot bank next year on hoped-for turnarounds by so many pitchers.
And the notion that a supposedly "decent" fifth starter is sufficient has been disproven by the Reds time after time because borderline to poor starting pitchers, with a couple of bad breaks, often wind up with ERAs in the 6s and 7s.
More good starting depth. Critical for 2009.