When I considered myself an orthodox Lutheran, it was based on the fact that I held to the historic creeds of Lutheranism, read in a historic context. The Lutheran Symbols call Mary ever-virgin, says the Saints pray for the Church, they do not disapprove of prayer for the dead, they call for private confession and absolution, call the Bread and Wine truly Christ's Body and Blood, they call for all communicants to be examined and absolved, Justification is considered in more than just the forensic sense, they call 2 Maccabees Scripture, they call for all traditional Church rites to be kept and practiced with utmost reverence as long as they do not contradict Scripture (such as certain Roman additions), they say that all bishops in the Church are equal, they say that children should always be taught to make the sign of the Cross, and that the baptized do have free will to cooperate with the Holy Spirit, and finally, they do not speak of the Lutheran Church as a "denomination", but as the continuation of the One Holy Catholic and Apostolic Church, in the West.
So it's not about being strict, but about (relatively) holding to the orthodox doctrine of the Historic Church.