He still reads the game the best of Barca's defenders, is the best passer (well maybe with Alba though different) and is the best Barca target man in the box. Ideally he never gets left 1 v 1 with a top striker. Umtiti has his drawbacks too--sometimes too slow in mentally processes where the threat will be, and can play flippantly (lose the ball when getting cute). As far as I am concerned I'd only trust Diego Godin more/is more complete than these two, maybe Varane and Van Dijk too. Anyway, with Pique/Umtiti/Lenglet (and Vermaelen as a short term 4th and Marlon maybe a long term 3rd/4th), CB is one of my last worries with Barca.