I haven't read Gladwell's book, but I've heard more than a few different radio programs on this subject (e.g. radiolab, freakanomics, etc), that interviewed Gladwell (although not exclusively).
One could argue that the point from Gladwell's side is that hard work and determination are more important than genetics, and I don't think this is an unfair characterization. Gladwell seems to phrase it slightly differently. That it is the love that certain people have for certain pursuits that gives them the motivation to *easily* put in the 10,000 hours of work to become an expert. Sure maybe some people require 22x as much *deliberate* practice to become a master. Maybe the person who only spent 728 deliberate hours of practicing spends 24 hours a day thinking and dreaming about chess (i.e. a lot of non-deliberate hours). Maybe the person who required 16000 hours of deliberate practice, actually hated chess and only did it to please his chessmaster father, etc.
Even if Gladwell's view turns out to be true, it simply raises deeper questions. What causes some people to love certain pursuits and not others. In the same way that genes can cause exceptional predisposition to skill of a particular type, isn't it just as likely for genetics to be able to cause exceptional love of a particular thing like chess, music, etc.
This deeper point that born with the love of chess *may* be a more important attribute than being born with a predisposition to be good at chess, for me, is not so much an empirical question as a philosophical question, if only for the reason that I think these sorts of questions are very difficult to answer empirically.
But if it is true that the passion for something like chess or music can be genetic (and I don't see any reason why this wouldn't be the case), then this is simply an alternative path for genetics to play a role in becoming an expert, rather than an alternative *to* a genetic path.