From my own point of view , out of Khedira , Bender and Morgan Scheinderlin , the latter is the best bet . He is younger , best tackler , good passer and would need no time to acclimatise to EPL . He is the best defensive minded of the three . He might also be the cheaper and easier to get .
Kedhira is a top player but will need time to adjust . He will command a top wages( they talking about him being top earner at Arsenal if he signs ) which will not always be welcome by Sanchez , Ozil , walcott and Ramsey . why should a new guy get more money than everyone before even kicking the ball ?
Bender is also a good DM but will need time to adjust . His reluctance to join Arsenal after all these years Arsene has been after him show he is not really keen to swap his jersey maybe just for money .
We need players like Cabaye who went on strike just to join Arsenal even though his dream did not come tue .
Schneiderin will never say no to Wenger .