He's right that they aren't the best in MLB. I still think they might be the best in the NL. Here's my (rather disjointed response):
A few things:
1. The Rockies get more of a hand than any other team in with tRA, because we’re using David Gassko’s batted ball park factors (linked here: http://www.statcorner.com/tRAabout.html). Their k-rate, for example, is boosted by a mlb-low park factor of 0.89. Home run per outfield fly correction is similarly high (second-highest in MLB) at 1.22. Virtually everything except walk rates are adjusted in the Rockies’ favor. Coors’ is the best hitters’ park in baseball, though, so you’d expect them to get the most help.
2. If you take their 4.10 FIP and correct for park, where does that put you? I haven’t done it myself, but I’m guessing pretty close to the league lead. You can use 0.89 as a park factor for K’s, 1.00 for BB’s, 0.97 for HBP (all from Gassko), and 1.08 for HR’s (from patriot). … ok, let’s do it:
Raw FIP = (13*67 + 3*(223+20-10) – 2*468)/633 + 3.14 = 4.10
Cor FIP = (13*61 + 3*(223+21-10) – 2*526)/633 + 3.14 = 3.81
That’d tie them for third with SF in FIP (without doing park corrections for those teams). As you said, not the best by this measure, but extremely good.
3. It’s worth mentioning that in addition to the DH issue, I’m not correcting the pitching stats in the power rankings for league difficulty. That gets tacked on at the end (which lets people ignore it if they want to). So yeah, the Rockies aren’t the best in MLB. But they are at least among the top 3-5 staffs in the NL this season.