First...I searched this subject and could find no up to date info...Are there any known mechanical issues with the R 1200 GSA ? I had a KTM sales person rip into me when I asked when they were going to go to a shaft drive.. Seems shaft drives have a checkered past?
You have to go pretty far back to find "checkered."
Back around the millenium to 2004 ish, there were RARE issues with the clutch splines. The reports though rare, made good copy for the forums. BMW did not take ownership and those afflicted were faced with a breakdown and a pretty hefty repair cost. So there was that--and owners were pissed...after that up to maybe 2010?? there were some issues with the final drive, including failure. Again, BMW did not own up to that, but again a rare thing. Between about 2006 and 2011??? they used a fuel strip as a sensor for fuel quantity. They regularly failed and BMW issued a "fix them whenever it happens" order to all dealers in the US. They have since gone back to the tried and true float. After that nada, afaik.
The GS is a wonderful bike, the boxer engine has its quirks, mostly in funny noises, but is durable, reliable, fun, and easy easy to work on. Is it still true you have to remove all the fairings to change the oil on a KTM?
What you are seeing is salesman BS. Find another dealer.