Two things I really appreciated, is that we get to see Mando finally get beaten up by an opponent and almost lose, plus he is outsmarted by Moff Gideon. Those are the two things I felt were missing all season.
The CGI looked fine to me. Yes, Luke had a bit of the uncanny valley going on. But it looked better (or less jarring) than what they did in Rogue One, and they obscured his face as much as possible. Plus, keep in mind that this is still a tv show. And lets also not forget that Luke's cameo was important to the plot, where as CGI Tarkin and Leia in Rogue One were completely unnecessary.