Imagine that the congregation of your church just learned that the pastor has been plagiarizing other people's sermons found in books or online. The number of sermons he plagiarized is over 50 over last five years. The actual number of the plagiarized sermons is yet to investigate. By the way, the pastor has no intention to resign and the elder board has no intention to fire him.
What would you do? Would you stay in or leave the church? Why?
It's truth that we want to be preached. Unchanging truth, the same as it was 100, 300, and 500 years ago.
So, at the very minimum, a pastor should be saying just what other pastors have said, in essence.
Sure, we want him to tell us where he got other wordings from, because that is the American way, and being American, I prefer to know what I'm hearing as to the source. But, either way, I still need to carefully consider whether the message aligns with scripture.
And....
Were the sermons effective and powerful to help people find and stay in Christ?
Do you see the fruits of the spirit in the church?
That's what does matter.
But, there are 2 potential problems that could happen.
1) Would the pastor himself like his own wordings when used to be used with attribution?
2) The real reason for attribution is to prevent us from thinking that wording is Gospel!
E.g. -- I want attribution in that this is merely my wording, me, a mortal, so much less than His Words, by far, and don't mistake my mere wording for His!