I haven't followed Argentina much, so can't really comment on their chances. But in recent WCs imo they had good players but didn't make a good team. Has this changed now?
I just don't have any connection with them, I started disliking them when Simeone got Becks sent off
(but I like his Atletico though!). My dislike for them changed a bit when we got Tevez who I just loved when he was with us! Obviously after he left all my sympathy for Argentina was gone.
Then regarding Messi, I don't have anything against him and he definitely is one of the greatest ever, but my favourite Barca player has always been Iniesta! And then Xavi! I just don't have the desire to follow Messi with Argentina, he doesn't interest me that much. Then I like Aguero and Di Maria, but same story, can't be bothered to follow them too closely.
I'll just relax and enjoy their games with my neutral feelings I guess!