Arthur is a solid player and when he arrived it was a breath of fresh air to see a player able to keep the ball under pressure from the opposition press and recycle the ball. Especially after 16/17 and 17/18 with an ageing Iniesta we lost that profile in midfield. Of course Arthur's press resistant naturally grew comparisons to Xavi which to me then created unrealistic expectations of what his level is. Xavi was more conservative in his early career like Arthur which is true, but there was plenty of times he completely dominated a game, e.g Spain vs England 2003. However at that time, a midfielder of his stature and play-style wasn't lauded like it is today before the Pep era so they kind of went under the radar. Arthur has never shown the ability to dictate a game like that.
Arthur has always had solid traits but severely lacked in the creative department, always quite hesitant to play the ball and holding on to it for too long. A midfield 3 of De Jong-Busquets-Arthur is at pedestrian as it gets and it's shown in the games they've started together. In fact the ironic thing is, that when FDJ arrived it highlighted Arthur's weaker traits more as FDJ was able to do many of the things he does.
He has had moments where he's played some great passes, but they don't happen nearly enough. You can bemoan the lack of movement up front, which is a problem but consider Puig the other night playing a ball that penetrated two lines and took out 6 players. Puig also has the natural instinct to play passes like this always trying to progress forward, take risks, Arthur doesn't.
Perhaps had he arrived and we had a coach capable of developing players e.g. Pep, Klopp etc he could of developed this side of his game. Considering he cost virtually nothing in todays market from Gremio with zero European experience, he has on the whole performed well but I don't think losing Arthur is at all catastrophic, just having Pjanic as part of the deal is the only downside to me and not straight cash.