As ever on the caf, most folk are set in their opinion and will not consider any other possibility.
Smalling didn't do a huge amount wrong today. Rojo and Blackett both had shockers, and Smalling was returning from injury and only had to come on to replace Evans - we don't even know if Smalling was 100% fit (obviously LVG didn't have him starting, this may have been purely tactical or may not have been).
This season he has been pretty solid at the back, in my opinion less error prone than Evans or Jones. His strength is not on the ball, this is true, but now that we have a shielding midfielder like Blind (Carrick would fill this role when back from injury as well) he should have an easy outlay.
Look at the other top teams, they aren't relying on their CBs to be playmakers. In a 3-5-2 you need the central CB to be comfortable bringing the ball out, but in a traditional back four there should be other players coming to receive the ball. This is what Gerrard does for Liverpool, Arteta for Arsenal, Barry or McCarthy for Everton, Matic/Ramires for Chelsea and Fernando/Fernandinho for City. We have for a long time lacked midfielders who will do this. We now have them and as the team settled we will see the improvement I hope.
Smalling has in the past been very composed under pressure and been a very capable ball player, I expect the current issues are purely mental. Nonetheless he would benefit from having another experienced CB alongside him rather than the likes of Rojo and Blackett.