Actually Pep has rotated less in 13/14 than Heynckes did in 12/13 - the key players even played a lot more Saturday matches than they did in the year before. But whereas Heynckes had his bench eleven ready for the last months and had prepared them since months getting even the third/fourth league teams around midweek to do friendlies with them - Pep let a lot of his regulars play with totally newbies as soon as we won the league. You can see even today that Heynckes uses the full team much more than any coach before. Apart from the goalkeeper no player has played more than 80% - and even Lewy and Kimmich would have played less if not both Bernat, Alaba and Müller would not have been injured or there would have been a striker replacement before winter. And even the benchiest bench player Bayern has with Rudy has gotten around 1300 minutes matchtime in all competitions.
And about injuries - every injury takes 2 weeks longer with Heynckes as he is absolutely careful with his players. The period from muscle injury to return to running and return to team training stayed the same - but whereas Pep let the players play again short after they are in team training Heynckes waits another 2 weeks...
