As said earlier, the reading order should probably depend upon the reader themselves.
The reason for suggesting the different from printed order for reading is that Terry has improved a great deal over the course of the years. So if a new reader, after hearing a great deal about what a great writer he is starts with his earliest works, they may feel that the praise may not be warranted, and just stop reading or if they do continue, may not go on to read one of the better books.
As such, if they start out with one of the better written books, once they are hooked
they can go back and read the earlier books, and not be put off by the differences in style and quantity as they are already aware of how good he currently is.
Well, That my two cents, pence, paisa, (whatever!) worth.
