The slope in value between SP picks in the last 7 rounds is very shallow. It's there, it's just not steep enough to warrant any need to jump on pitching.
Andrew Cashner is basically is valuable as Jeff Samardzija. Two years younger, probably projects for a bit more K's and a slightly higher ERA. Those kinds of comparisons exist all over the round gap.
The differences between Maeda, McCullers, Gausman and say Heaney, Velasquez are maybe 20% skill and 70% preference. 10% mystery.