That was Zubi, and he deserves credit for finding and signing Lucho, Rakitic, MAtS etc. Bartomeu just went with it, he knows very little of football and basically let the sporting director do his job.
The funny thing is that Bartomeu fired Zubi, the one who signed Lucho in the first place, when things looked at their darkest... But now that the team and Lucho managed to turn things around, and end the season in a historic fashion, he renews his contract. Not exactly rocket science. I honestly can't see how Bartomeu deserves much credit, if any, for this treble. He has done an okay-ish job in making some good decisions now that the elections are looming. But are we really ready to trust him in leading the club for another full presidential period when he doesn't have to pull off popular moves in order to keep his job? I'm not.
The list of horrendous decisions Rosell and Barto has done is enough for me to want something new. He has patched some things up after Rosell, that's it.