Hmm...
I find it a bit funny that there are some who apparently think that John Newton actually sat down one day and wrote a song with 17 verses, intending for his congregation to sing it in church. As has been already pointed out here, there were six. Ironically, the verse being discussed here (When we've been there...") was not even one of the six written by Newton.
I once heard a British preacher online (Roy Hession or Leonard Ravenhill, I forget which) who was talking about his trip to America where he observed that all the songs, including those by Brits such as Newton, Wesley, etc., were all chopped down to 4 verses in American hymnals and invariably the song leader would have the congregation sing only 3 verses. So, yes, the British tradition is/ was for a few more verses but no one in their right noggin would expect people to sing 13 or 17. Come on people, reality check.
There is a rich folk tradition of adding, changing, deleting verses but those sort of "folk" are more known for their common sense than folk you might encounter online. But hey, if any of you want to get together and sing a 17, 19, or 28 verse version of A.G. well hey, go for it!   just don't put it on youtube, there's enough nonsense on there already ;-)
Peace & God Bless