I believe lucho and his staff can help Gundogan find his best form.
The team as a whole was a mess last season. Now they're in sensational form and physical shape. Many thought Messi was finished; now he's hit new heights, even by his standards. Pique and Dani Alves also found their best form in time.
As with the transfer ban, Gundogan himself said he was willing to wait until January if the deal suited both sides. Barça can also sign him in the summer if they wanted, it's not like they're short of transfer deal options. He would just have to wait until
January, like Aleix Vidal, for them to register him so he can actually play for Barça. The time spent out would allow him to get adjusted to Barça and build chemistry with his new teammates.
Gundogan wants only the best for Dortmund; he isn't going to pull a lewandowski and join Bayern for free. He seems set to leave dortmund either this summer or next January. Him leaving as a free agent simply isn't happening. Because of this Barça couldn't sign him for free next Summer even if they wanted to.
Buying Neymar, Suarez and, to a lesser degree, Rakitic, was a gamble for Barça. Yet all of them played a key role this season in winning the Treble. None of them, with the possible exception of Rakitic, seemed to fit the team. But once signed, they were accommodated perfectly. Surely Gundogan, who seems a better fit than all three of them initially did, would fit perfectly in Lucho's system?
As a faithful cule, I have absolute faith in Lucho and Barça. If they do indeed sign Gundogan, I have no doubt he will do great at Barça.