The title is not entirely correct. They don't plant to "introduce" conscription. Germany had conscription from its formation of the Bundeswehr in 1955 until it was put on hiatus in 2011 because people back then thought that Ivan was no longer a problem. So what they think about is not "introducing" but just reactivate it.
The changes will be that while before 2011, conscription was only for men, it is planned to be for both sexes, and military service will no longer the one preferred service (back then, you had to go through quite some hoops if you did not want to serve in the Bundeswehr and do your time in e.g. social services). This time, the military option is just one of several that can be chosen.
At this stage it's all hot air. Nobody has even started talking about how to finance it and the defense minister isn't even 100% sure he will get his requested additional funds for the next cycle. When somebody asked him about the topic he replied that he isn't categorically against it but he would have to finance (and restructure, as the necessary infrastructure for it has been degraded/scrapped) more important topics first.