Everything was fine until Rosicky came off. It allowed Olympiakos to attack more comfortably knowing Arsenal had no creative CAM anymore. Otherwise I hope that the rest given to the rest of the players helps them turn on the style switch again.
As for finishing second in the group doesn't matter, there are really tough teams to play against in the next round either way.

Arsenal are in desperate need of good mid-fielder and striker combo.

To be really honest i would be more surprised it Arsenal did win..