Honestly, it's quite normal for big teams with a lot of internationals to see more minor injueries (muscle problems, fatique etc.) in a WC year. Vidal was forced to play and stay in shape for 1½ month while injured, Pirlo is old and haven't got enough time off in the summer etc. etc.
Then there is a part of randomness, as there will always be with these kind of things. I think it's way to early to blame Allegris training methods. If it's due to a wrong training schedule, Conte would have as much of the blame, but i don't really see it that way. Look at Morata - injured in the first day with the club. Sometimes you will have several injuries, why do people always have to give death a cause? (is that a saying in english aswell? It is in danish)