yay era. he has an xfip over 4 and a k rate hovering around 6, with a walk rate almost 2x as high as his 2012. it's pretty fair to say he's a pitcher that the highest scoring offense in the NL should have been able to do more against in a crucial game.
I mean, he also isn't walking many people, has an good WHIP, is giving up basically no home runs meaning he is constantly getting people to put the ball into play in a way that is letting his team consistently field it to keep from having big innings.
Also highest scoring offense in the NL might be accurate, but not all that impressive given even the last place Rangers have a higher scoring offense :P
but rangers jokes aside 7 of the 14 other teams in the NL are with in 20 runs of the cubs.
the main point being regardless what his extended stats say he has been very effective at not having many runs scored against him this year, and the "highest scoring offense" really doesn't mean much when it comes to the NL in regards to how it should be able to do something against him given half of the teams in the NL arguably have nearly as good offenses by runs scored.
I mean extended stats are fun and all, but they don't dictate reality. Wade Miley has been highly effective this year, and whether it appears to be luck by the extended stats or not, when you have almost a half of a season's worth of data it shouldn't really be that surprising when the best the "highest scoring offense" could do was slightly raise his ERA.
I mean by your criteria someone like Mark Buehrle is a horrible pitcher with a career xfip of over 4 and a k rate of 5.13 and yet he had a perfect game, a no hitter, and was a 4 time all star and really only had 2 bad seasons over a 15 year career.