Lucho's downfall comes down to his own system he created.
What worked during the second half of the treble season and the first half of the Spanish double was no longer working as of 2016. It was a flawed system to begin with as Lucho sacrificed the midfield which was considered the strongest aspect of Barcelona and had the creativity duties come down to Alba-MSN-Alves for the most part.
This season he tried to use Mats as an additional creative outlet which was apparent in the Bilbao match in the earliest part of the season while we sat back and Umtiti and Pique were clearly instructed to pass to Mats where he can boot it up field to break Bilbao's high press and create a counter attack opportunity for Arda, Suarez and Messi.
The use of long balls by Umtiti, Masche and Pique to try and create chances for MSN/Arda as well. while he tried to evolve his system in a couple of areas he still refused to address the glaring problem and that was the Midfield.
I'm convinced even he doesn't know what he's got and what to do to bring out the best in guys like Gomes,Rafinha,Denis,Rakitic etc. He's having them all play the same Generic role. aka pass it to MSN as quick as possible and play as makeshift Fullbacks so Alba-Roberto-Vidal-Alves move forward and do the attacking.
Perhaps I'm stubborn but I'm waiting for a new coach to implement new ideas and to see how guys like Gomes,Denis etc would perform in a different system before throwing them to the wolves this early.