Three things:
1) We signed quite a few players late-on in the transfer window so DC didn't have much time to experiment with the full squad and different formations/combinations of players, etc. Basically, he's doing that now.
2) We've had a high player turnover which means starting from scratch with formations/combinations of players and that takes longer to sort than when a squad has been largely settled for 2/3 years.
3) I think DC thinks the players can cope with it and that the pay-off in the medium term is worth the short-term risk of being Tinkerman.
Having said all that, you'd want it to settle down at some point.