I've said before, I do believe he had health problems in 2010-11 that contributed to how anonymous his performances were. And I do think recovering from that helped improve his level.
But I do not believe that Chris Froome ever showed anything remotely like the talent level that he is showing now, before the 2011 Vuelta. As I've said, I thought maybe if things went well he could be a Chris Anker Sørensen or an Egoi Martínez. And that at Barloworld he wasn't even the most impressive young African rider.
Also, a lot of the Team Sky sports science stuff has been shown to be nonsense for a couple of reasons. 1) Froome admitted not using some of it, not warming down post stages sometimes and not being in a wind tunnel, and 2) the argument was made that a reason he struggled was because he was technically and tactically poor, and improving this helped him become the destructive force he is today; however his position on the bike is no less awkward, his TT position is still dreadful, and Sky have been shown to be rather lacking in tactical aptitude on a few occasions in the last two years, they've just been strong enough that the simple bludgeoning tactic has been enough to overcome their weaknesses in other tactical aspects.
You also have the factor that Froome's blood values under bilharzia will have been completely unusable as a baseline because the characteristics of the disease make it impossible to tell what his natural level is; he was offered an opportunity, almost unique among the péloton, of a total do-over on his biopassport.
So no, doping is not some magic wand that has been waved and turned Cinderella into a princess. But the chance that it has not played some part in the transformation are, to my mind, extremely slim, because the amount of inconsistencies, bendings of the truth, changes to previous stories and straight up bald-faced lies that the team have had to tell to explain it away do not suggest any better reasons. And we are talking about a guy who had no problem with cutting corners, breaking into a national cycling official's email account to commit identity theft to get himself onto a World Championships startlist and getting thrown out of a race for hanging on to a motorbike. He was about to lose the dream, or so it seemed, and among the atmosphere that is the professional péloton do we really think he would have changed to become one of the most morally upstanding members of the péloton?