I wonder if some people are saying tranny in general terms but the dealer actually only did a mechatronics swap? Maybe they are getting whole rebuilt units because the dealer doesn't want to deal with the hassle of tearing into the tranny case and instead just drop it and put whole rebuild in?
My tech told me that having an actually gear issue is an extreme rarity. The mech unit does most of the work changing the gears. There's a bunch of valves and a whole lot of electronics that are always working. They usually don't do anything to the gears on rebuilds anyway. They usually rebuild the valve bodies and seals and that's what the mechatronics is.
I'm glad more and more people are getting good results with complaining about this and getting the right fix. I hope they are all logged in and BMW starts to take notice of the problem. It's got to be something with this ZF tranny because a number of us all have the same issue.