The one thing Milton did reasonably well that Silva is horrible about is miss bats. That means a lot more balls are subject to three things: luck, the natural park affects of wherever he's pitching, and team defense. If Silva was a Red, two of those three things would be working against him.
Milton (05-07): 5.94, 5.31, 5.17
Silva (05-07): 3.39, 3.49, 3.89
So, let's say Milton averages out to 5.5 k/9, Silva to 3.5. That may be 1.5 outs over the course of the 6-7 innings they'd normally throw. Given all the other parameters of their performance, HR rate, BB rate, ability to take their turn in the rotation, not to mention the near-certainty that Silva would be pitching with a better defense over the life of his contract, I think Milton's better K rate puts little in his favor.