The problem I have heard many LCMSers decry in the SM route is that:
A) it was never designed to be a short/easy route to ordination for any old person. It was supposed to be initially for extremely remote congregations who might ordain a man in their midst to give them Word and Sacrament in their midst. Instead, it has become a simple route to becoming a rostered clergy for any old lay fellow working in many a megachurch who wants to be a pastor, but doesn’t really want the training.
B) Questions have arisen as to whether it is actually producing pastors who know their doctrine and are apt to teach. I know one guy who took a call a few years back and inherited a vicarage of one such SM student who knew all sorts of stuff about meta-narrative, but knew no doctrine beyond a Sunday School level. That is an example of someone who is not apt to teach.