Can you name one La Liga club currently in the same form as Barcelona? I don't think there is. I'm not judging Barcelona based on their preseason matches, but on their performance last season that they were the strongest team in La Liga and still have that quality now. This gives me confidence they'll perform well this season. The challenge for the La Liga title usually from Real Madrid and Barcelona, but I still see Real Madrid as the weaker team compared to Barcelona.
Concerning the Mallorca match, that i said it may be tough. I'm a real fan of Barcelona, and I'm not basing my opinion on highlights. Because last season despite Barcelona's victory over Mallorca, they gave us a tough time in both the first and second league matches, luckily we managed to win them.
You might be right that no team outperformed Barcelona last season based on their stats but that was last season remember? We can't say for sure what the new season will bring. They're still a good though but i don't like being overconfident about a future outcome , look at what happened with Real Madrid last season.. It turned out to be a bit of a flop for them.
Again, Mallorca isn't a very strong team,the reason there weren't more goals was probably due to the substitutions and the fact that one of their players(Pablo..)is on the Mallorca side. Still, Mallorca had two red cards and I think Barcelona should've scored more after that.
Those are my thoughts, anyway.