I have used both 6800 and 8000 rear derailleurs on my current bike. With the slightly longer 8000GS rd, it is slightly more difficult to remove the rear wheel. But here's the trick . . . you have to push the end of the cage down manually (a 1-finger operation) while moving the wheel downward. If you're in the 11 cog, the cage practically doubles back on itself and it doesn't want to pop loose as it does on the 6800.

Another idea would be to shift a few cogs up from the 11T so that the cage isn't at such a steep angle. If it's not at that sharp angle, the wheel should pop out just as on the 6800. Mine has thru axles, but I haven't had a problem since I figured out I have to push the cage down.