As much as Txiki had to prepare for Pep and he did so by organizing deals for KDB, Sterling and Stones amongst others. He also had to provide players for Pellegrini, I don't believe that Mangala, Fernando and Bony are bad players. They simply didn't fit in here and you could maybe argue due to Pellegrini's tactics they failed to adapt.
Mangala was very highly rated CB and whilst we overpaid a bit, I don't think anyone had concerns and certainly not after his first game!
Fernando, considered a bit of a bargain after his consistent performances in the CL and a strong performer for Porto.
Bony, a big physical presence which we lacked and we were buying the highest goalscorer in the country (by calendar year) Txiki isn't at fault that Bony didn't settle and then got sick and hasn't been the same since.