I mean like I said earlier this shouldn't be a difficult decision to make anymore. He needs to play week in and out while Vidal can make a rotational RB in some of games vs weaker teams. Vidal and Roberto simply don't have the attributes to be our starting RB here.
Roberto tried hard fill that gap Alves left but unfortunately he didn't have the pace nor the attacking contribution going forward we need out of a RB for Barca. During Lucho's time here, he heavily used Alves and Alba as attacking/creative outlets. But with Alves leaving and us having a RCM like Rakitic, the right side was totally dead. Roberto could theoretically work in a system where the RCM and RWF does all the creating and he just focuses more on the defensive side and occasional overlap.
Vidal, he's a pure attacking player and the Sporting department saw his games for Sevilla, and thought he would make a good Alves successor/rotation option. Problem is if you watch his games with us he plays like a winger that was forced into the RB spot.
He doesn't understand attacking and defending transitions, he rarely times his challenges properly and he cannot position himself etc. Stuff that a Right back needs to know. He relies a lot on his pace to bail him out when he makes mistakes but even with that he still struggles.
he's a hard worker no doubt he doesn't have the instincts a RB should have. He turns 28 next week and I seriously doubt he will ever improve in that regard no matter how much he plays this season.
Semedo might not be perfect either on the defensive side, but when you watch him play you can see the differences between Him, Vidal and Roberto. He plays like a Real Right back who possesses the tools to be the Right back we desperately needed since Alves left.
No one can be Dani Alves, but Semedo can be that guy who can pick up his old role as a strong creative RB while being solid on the defensive side.