Reflects poorly on the board in that a better buy could have been made relative to Pjanic for Arthur money. I'm not a proponent of an aging team.
Timing of the deal also wasn't ideal. Could have held off till CL ends to announce it. Because as it stands, we lost even a rotation player in the event of injuries. Yes, that's mostly Arthur's fault in not being a professional but the board could have better foresight.
Your points about his attitude, I already made and agree with...
Sure. Could have maybe gone for a younger player, but Pjanic's quality is not questionable. He is also never injured and is a model professional.
Arthur is turning 24 soon. It was the right move to dump the lazy, entitled sod as soon as possible for the best offer. In this current economic situation we would have been hard pressed to get a high lump sum of cash.
Had we waited for another year or two looking for a better deal whatever shine left on the bloke would have worn off, his problems would have only become more apparent and he becomes untransferable.
Board announced the deal early because it benefits both clubs financially to record the transaction in the previous financial year which ended in June. Not ideal for the players involved, but that's simply business. Arthur deciding to switch off after the fact is on him and no one else.
Ironically all his latest stunt has done is destroy and goodwill he had left with the fans. Even if you don't want to play just pipe down for a while since you'll be leaving in a few weeks anyways. Most Barca supporters still supported him the past two years despite mediocre performances, fitness concerns and off-pitch drama. When the transfer was announced they were sad to see a player they thought still had potential go. Now they're spitting on him.
This also reflects poorly to Sarri, Juventus any any future coach or club he goes to. Once you get this sort of reputation it doesn't go away.