What I think he has improved the most this season isn't about stay away from injury but he doesn't make rush and unnecessary sliding tackles / challenges anymore which is also a benefit for him to stay fit.
The improved calmness doesn't take away whatever helping him stay injury free for the moment. Just a season ago, it sounds like he got injured just by driving to training ground, unless he tackles everything he sees on the street.
Rojo is doing a lot of passing from the back, in addition to communicating a lot with Jones and LB. Of course, he is not Blind on that aspect of the game, but he is doing quite well.
What is impressing me most, is that the partnership is just working well, they have a good understanding of each other, cover well for each other (and for the fullbacks). Long may it continue!
While Blind has better play making ability, it's also more predictable as he usually took longer for his long ball, and manager targeted him when we not in possession phase leading to we have a deeper defensive line (not box camping but deeper than with RoJones combination). With RoJones we can create tempo from the back and move the ball quickly from side to side. Even tease up opponent attacker to leave their position and ball chasing. That helps breaking opponent defensive shape a bit.
Last season, the little best football we played all season coincided with Carrick and Blind playing as our CBs, when we could control tempo from deep and move the ball around quickly and effortlessly. However, Carrick and Blind can't offer proper defensive assurance, understandably due to they're not CB by trade.