I don't remember seeing too many live Arsenal games towards the end of last season. I did notice that their results improved when Coquelin came into the team though. Mertasacker and koscielny sounds like a good partnership to me on paper so they might improve with a good keeper behind them. A quality striker is a must i think. Giroud is good and would be a good option but he dosen't seem to link up with the midfield all that well.