Oh, no doubt. I'm sure he can make a difference, and I'm sure he has done/continues to. But like many things with Sky, the problem is that the transformations that have happened on their watch have been so vast (and in some cases sudden) that it makes it difficult to believe any such factor that we have been advised of so far, even in combination, is legitimately responsible. As I've said before, I believe that Chris Froome did, quite genuinely, have bilharzia. I believe that for all the mockery they have received, some of Sky's marginal gains theories have indeed yielded incremental increases in performance (even though said marginal gains were trumped in huge quantities before the 2010 season, natch). And I'm sure training and psychological coaching has an effect as well (as long as that psychological coach isn't distributing Gute-Laune-Tee, whoops wrong thread!). But even all of these factors combined don't account for what I've seen from Chris Froome, because the change was not the gradual incremental aggregation of marginal gains and improved mental preparation that then enabled him to finally race with all the shackles off when the bilharzia was cured... it was one day the Froome that loses 20 minutes in hilly stages in the Tour de Pologne, and the next the Froome that rides GT winners off his wheel breathing through his nose.
There are many legitimate reasons that Sky have been able to produce improved performances from their riders. But none that they have presented to me so far are enough for me to swallow the extent of the improvements we have seen from Sky riders - bearing in mind the less sanguine other elements that have been discussed ad nauseaum such as the presence of Geert Leinders, Mick Rogers, Brailsford running away from questions he doesn't like and so on - and cast away the doubts that have been characterising my view of the team for over two years.