Arsene Wenger made some questionable signings in defence in his final few years at Arsenal, but most of his former defenders have now retired. Per Mertesacker is now heading up Arsenal’s academy, whilst Laurent Koscielny has become FC Lorient’s director of football. When Arsenal last finished in the top four under Wenger, this was his starting partnership in defence, with Brazilian centre-back Gabriel Paulista rotating in, with sometimes disastrous results. Gabriel Paulista joined from Villarreal for around £10m in January 2015, but after an initially bright start, his defensive deficiencies b…