He was just clumsy with his body in certain situations but i get why you thought he was good, he did some things very well too. I've read this thread before and its often a lot of people who don't seem to understand its possible to do both good and bad things in a game.
Like this. I've seen Ramos, Pepe, Varane, Rio, Vidic do exactly the same type of clumsy mistakes now and then, but they are still forgiven right away and appreciated because they are already rated as classplayers. Somehow Smalling makes those mistakes once in a while and it sticks to his reputation, like "Smalling in a nutshell". That's ridiculous! He is not rated, that's just it. Seems like we are now not supposed to have a good defence, and even though we're certainly not perfect we always gets criticised quick for our defence. It seems like a lot of people miss out on some excellent defending, because they are not looking for things that doesn't fit their overall perspective. I just don't get it (Sorry for bad English on this)