>>I am concerned when people here use the term "unbiblical methods".<<
You should be more concerned for the churches that implement them.
>>don't understand what one means by "watered down".<<
Not giving the full message of the gospel. Not saying a word about sin and its' vileness for fear of offending the newcomers. Only preaching about the benefits of salvation, not WHY it's necessary. Preaching fluff instead of meat.
What I am trying to say is that I question if the methods are "unbiblical" or just non-traditional.
Jesus was/is quite non-traditional. Change is a good thing sometimes. Judging a tree by it's fruit (and I don't mean monetary) is also a good way to look at this.
Regarding the fluff thing. What I've seen of Warrens work (I looked up some of it) DOES include meat. Like the apostles, some was "spiritual milk" and some was meat. I guess any judgment of Warrens words would have to consider the audience at the time they were being said