Tbh I feel like Tugba would actually fit the current Vakif. One of their biggest issues this season is that they have 3 very similar OHs: young, with potential in attack but vulnerable in reception. So even if Guidetti knows that the passing is what's bringing the team down, what is he going to do? Sub Derya in?
Daalderop also doesn't get a lot of kills against top teams (iirc she had around 5 points vs. Conegliano), so she just becomes a liability in reception without much to offer in return. At least Tugba can stabilize the pass so that Gabi doesn't have to cover half the court.
I agree that they need a defensive OH but not necessarily Tuğba. She is not a bad receiver but not a great one neither. I wish Vakıfbank could have get Yaprak instead of Eczacıbaşı this season. Eczacı is overloaded with good Turkish OHs while vakıf is only relying on worse of this bunch, Derya. Even Şeyma or Meliha could have been more useful as a bench player in vakif than Derya this season