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Tim Hudson (59% Career GB%, 6.1 K/9, 3.4 ERA)
Derek Lowe (63% Career GB%, 5.9 K/9, 3.9 ERA)
Roy Halladay (55% Career GB%, 6.9 K/9, 3.2 ERA)
Of course you already mentioned Felix
These guys didn't carve out a few mediocre years, these guys competed for (and in Halladay's and Felix's case won) Cy Youngs. Not saying that it's not used by a lot of mediocre pitchers, I'm just saying it's not 1 pitcher per generation that can make it work. Could these guys have been better had they made more attempts to get batters to swing over their heads? Who can say, probably not for Derek Lowe, though he's the weak link on the list, but would the rest of them have been better with an extra 1.5 K/9 and an extra .2 HR/9?