I don't routinely watch la liga, but the couple of games I have watched, it did seem that Barcelona were being prejudiced against in the referee decisions.
Though, I think that's the result of refs trying to not appear to favour them cos of the Negreira case rather than some other conspiracy.
Luton definitely have a worse team than them, but just look at the contrast of their performances. He should be appreciated for the work he has done, but sometimes change is just necessary.