Last season they had very simelar strike rates whilst Zlatan was intigral to everything good about Inter. Barca had Messi and Iniesta having their best ever seasons and they were the outstanding players in the team.
Another point people seem to be missing is that they want Zlatan for a reason, not to be another Eto'o but to give another dimension to their play. They know that at times they might need to have a target and Ibrahimovic is one of the best. He showed how good his hold up play was against United when he was as isolated a player as i've ever seen.
They are losing a more natural goal getter but they will be getting a player who can adapt to situations, equally adept with flair as he is with route one football.
THis is the reason Guardiola and co want Ibrahimovic. It just so happens that Eto'o wont sign a new contract and it is now or never for Barcelona to get something for him or risk losing him for nothing.
Of course we dont know if he'll be great or not. I think he will be but then i'm his mother