The larger BMWs with the shaft drives seem to have more failures. And I'm not sure if BMW has changed the design of the final drive to eliminate those failures.
If you are talking about the rear drive bearings - they changed the design in 2011 I believe. For some reason the wheel side oil seal was on the inside of the wheel bearing, and some folks had early bearing failure (while lots of others had no issues and put on many, many carefree miles). Speculation came up about maybe those folks on the GS bikes did more water crossings.....or pressure washing that resulted in the bearing being contaminated with water or dirt.
Last fall I took the plunge and bought a nice used R1200RT for riding double up with my wife. We rented one for 2 days on a trip to Tucson, and I fell in love with the bike. If I had taken a 30 minute ride on one I likely would have said "nice bike" - but after spending 2 days on it I really fell in love with the smooth ride, great handling, power and comfort, and it was the most comfortable bike my wife had ever ridden on as passenger (I am sure the Gold Wings and other big bikes with the Barcolounger rear seats are comfy - but they are too big and heavy for my 30" inseam and 170 pound body). I read about the high cost of BMW ownership and repairs, and the reported failures - and I decided to take a risk as I do most routine maintenance myself....and there are just too many folks that have ridden BMW bikes for 100,000 plus miles that have never had to do anything more than routine maintenance - however the ones who have problems are far more vocal than the ones who never have any problems.
About 12 years ago I started to burn wood for heat. I needed a better chainsaw and started looking around for a heavy duty mid size saw. The Stihl MS260 was a mid-size commercial grade saw that seemed to be very popular with professionals, and when the tree trimming crews would show up they would most likely have the MS260 saw, and a smaller top handle saw. What confused me was I kept seeing them on forums with running issues, broken/used up ones for sale on Craigslist, etc. I wondered how a saw that wore out and broke could be so popular with the professionals? It turns out the MS260 was very reliable and durable and there are hundreds of thousands of them out cutting wood everyday - and a few of them break or get abused or worn out over time....and those are the ones you see on the forums or Craigslist with the owners complaining (the other folks are out cutting wood and not posting on forums).
I think a lot of this happens in the motorcycle world as well. A few folks have problems and start posting on the internet - and before long a bad reputation and rumors can make a problem seem bigger and more common than it really is. I think it is "Phil" on this forum who has had a couple of rear drive failures - and yet most of the NT's don't ever have that problem. On another forum there is a member that complains loudly about any motorcycle that uses an alternator with brushes - as 20 years ago he had one wear out and fail on his Yamaha. It is far too easy for us to accept some of this "fake news" as being "fact". I do accept that there are some real issues that plague motorcycles - like the NT saddlebag latches, the Suzuki Savage head plug and cam chain tensioner, rear wheel bearings on the Buehl Ulysses, FJR rider heat issues and other things that are well documented - but I believe there may be a lot of unfounded rumors as well. (We had a Subaru Outback that gave us a lot of problems and we will never buy another one - and yet most folks praise the reliability of their Subaru).
I sold my NT not because of anything that worried me about the reliability - but because it was just a bit too small for my wife and I, and it did not allow us to take enough luggage if we go on a trip.....and because we rented an R1200RT that proved to be so much more comfortable for us - I am 62 and this is likely to be the first and last "luxury" motorcycle I will ever buy. If I was riding single I most likely would have kept my NT.......or I really do like the BMW F800GT! As noted in this thread....no other builder makes a good mid size sport touring bike......it is a shame.