I'm sorry but that's not what I said, you shouldn't twist words like that.
Gundogan doesn't go from world class to non-league standard, even if you are embellishing, his level of play is always high.
But as dom mentioned above, and as I noticed these last 2 years, he isn't his best when playing with David as both are too slow to drive play forward, and if they are both our 8s the performance looks bad and everybody blames Gundogan.
As a 6 he is by far better, and I most definitely disagree with you here that he has had many poor performances as a 6. He might have had some games where he didn't make the best decision or he didn't go in for that tackle, but taking his entire game into account, he is one of the best 6s in the world... I think he is comparable to busquets in terms of quality here. I stand by it, his performances last season is my proof, where is your proof he is so poor?