I don't think anything is wrong, per se. But the notion that in 2015, we don't have more widely used fancier technology on stethoscopes is interesting. There are some problems in how stethoscopes are used, primarily because a lot of skill is required to interpret the sounds and many doctors could be and actually are poor at this. There are many studies which show this, for example [1].

[1] http://pediatrics.aappublications.org/content/105/6/1184.sho...