Maybe Xavi is doing well in the La Liga but the fans would like to see more than that. Xavi will need to prepare his players and strategies special to Champions League games from now on. They have a potential so they should go for it.
Comparing Real Madrid with Barcelona will never end, because forever they will remain rivals, of course, each individual has his own opinion for Real Madrid and Barcelona. So yes, I think there is no point in comparing Real Madrid to Barcelona, especially when you compare it to a different tournament. Meanwhile, if you only compare Real Madrid and Barcelona only in La Liga, I think Real Madrid still has a better record too.
But apart from all that, I personally really appreciate Xavi, because since Xavi became coach of Barcelona, in fact Barcelona has been very good for results in La Liga. Even though Xavi hasn't been able to deliver great results in Europe, but I think so far Xavi has been good enough in building Barcelona to have a very good performance in the domestic league.