If his drop in form is due to fatigue the solution is simple: stop playing him. I haven't watched the game yet as I just got home from work (Actually turning it on now) but judging by the unopposed negative comments he most likely wasn't one of our best out there. At what point do we stop saying he's fatigued as an excuse, and just... stop playing him? For this reason I find it hard to believe his dip in form is actually fatigue related at all. Yes he's played quite a lot, but perhaps the Chinese league isn't very tiring, who knows. Considering a player with no dribbling or passing ability was able to be a superstar over there, it is quite possible the average game in China amounted to a regular training session in terms of intensity for Paulinho, and if that were the case, he really wouldn't be as tired as made out to be, would he? I don't think Brazil and Barca both are just total idiots that can't see how tired Paulinho is and that both teams find it impossible to play without him, especially if this current nightmarish form is due to fatigue.
Now, I don't think his status as a player with no European experience outside of failing in England is the end all be all in regards to judging him as a player, but outside of an admittedly hot start to the season his play has stagnated greatly. He's not the first player to start off well before becoming a flop, and he won't be the last. At the end of the day, we signed a player from China for 40m who is 29 years old, who has essentially 0 European experience, and outside of the first few months he has been a total disaster.