Sorry mate but that's outdated bollocks. May have been true a few years ago but not of last season. We pressed harder and more successfully in more games than any other team in the league. We may have lacked leadership or *character*, but the problems you talk about just aren't backed up by any facts.
Set pieces, Denilson, Eboue, Squillaci, balls over the top and freekicks/Penalties are we shipped the most number of goals in the league last season. Yes, defensive organisation and drilling will help things, but the gulf between even Squillaci and Vermellaen is huge and more than ever I actually believe it has more to do with the individuals (physical attributes, temperament) than anything Wenger is or isn't doing.