After reading what you said, I think his main problem is timing slide tackles and the actual speed of throwing himself on the ground. The way he does it, the attackers have enough time to almost dodge the tackle, so yes, there is a problem. If he can get that down, like back in the days, I will seriously consider him one of the best defenders in the world. Sure, he lacks an aerial side despite his height, but I don't really blame him for that, as I myself am terrible in the air despite being decently tall where I play. So I agree that there is room for improvement, but I don't think he needs to be benched or doesn't deserve to start or costs us games or etc. I think his strengths make up for his weaknesses and Barca fans exaggerate everything to a ridiculous degree.
Time for him to start doing it like he used to then? I'm sure he could improve physically. No, I don't think he costs games at the moment either. Much of it is due to Valdes' incredible form though.
I also agree that the Barca fans usually exaggerate everything. Still, the performances are not as good as they could or maybe should be. That's the whole point.
People are now just criticizing Pique like they used to do with Valdes!
Last season for example, he recovered 4-5 crucial balls against Bayern yet people just talked about the owngoal!
Give the guy a chance, he was good last night!
I couldn't watch the full game last night but I agree with the Bayern example. He made some great last ditch tackles in that game. Shame about the own goal.