It's easy to speculate on ways that Barcelona may be stopped. The execution of the plan is a different thing altogether.
They have ran into trouble in the Champions League against teams that defended deep. Inter last year. Chelsea, despite ultimate defeat, in 2009. Manchester United in 2008. It is highly questionable, however, whether Arsenal could play effectively in such a manner. They are not accustomed to soaking up pressure and playing on the break. Most of the time, in the Premiership, they are the team with the majority of possession.
Fact is, any "plan" may well go out the window. Last season, there was no plan to sit back. Barca's brilliance pinned Arsenal back. This time, Arsenal need to be a little more ready, if possible, for such a scenario.
It's a long time since Arsenal could have been termed a counter-attacking team, though Walcott's pace and Arshavin's directness do offer the opportunity to spring quickly. They are more likely to try to break up Barca's passing high up the pitch. The Chelsea game ought to be the blueprint. But Barcelona, needless to say, pass the ball a lot better than Chelsea, or anyone else. And just as they are used to teams sitting deep, they are also used to passing under intense pressure, and playing through it.
When Real went to the Nou Camp this season, Mourinho changed up, perhaps believing that the players at his disposal could not defend the Inter had the season before. Real played a high line and tried to press, and got absolutely roasted. David Villa revelled in the green grass behind Carvalho and co, and Messi, Xavi and Iniesta all found time and space to pick defence-splitting passes. In other words, it's well and good to simply suggest that Arsenal should push up and put Barca's midfield under intense pressure, but without energy, organisation and controlled aggression, it could backfire spectacularly.
When it comes to the defensive side of the game, Jose Mourinho is clearly a better organiser than Arsene Wenger. Yet his team were hammered. The only hope for Arsenal fans is that their attack will prove more potent than Madrid's did, and make the most of the opportunities they will get against Barca's vulnerable backline.
At least Messi won't be running at Sylvestre, as in the second leg of last season's tie, but at an Arsenal defence that has looked more assured of late (with the disturbing exception of the St. James' Park debacle, when, in fairness, Squillaci's introduction and the absence of Song in front of the defence clearly bred panic).
There would be no shame in losing to this Barcelona team. And in football, as they always say, anything can happen. It's often forgotten that, despite their depleted line-up, Arsenal actually briefly led last year's tie beyond its halfway point.