I don't think Barca is a good fit for Mandzukic, he is very strong in the air but not the best technically and I don't see Barca changing their game and starting to cross the ball from flanks. But maybe they should consider changing game plan in the games where opposition parks the bus and standard tika taka football isn't enough to break them.
Exactly that's why i think it wouldn't be a bad idea to have some tenacous and hard working attacker that is good in the air, as we know that 99% of the Barcelona opponents park the bus, and sometimes someone like him could really penetrate that kind of bunker.We all know he wouldn;t be 1st option, but he doesn't have to be, since he is 33 yo but he is perfect for changing the pace of the game.
And he would fit perfectly as he knows how to win titles, and he was always the player for big games, when you need him the most, he will deliver, he always played good against big teams, and Barcelona always aims for titles.