I've considered sealing the rear wheel on my Twin for exactly why you've said. The reason I haven't is that it adds an extra mode of failure and I just don't get punctures regularly. Doesn't make sense when I'm comfortable changing a tube even if it does take longer.
On the Goldwing I had only a plug kit and compressor. I'm honestly not sure I could've gotten a wheel off of it for a more in depth repair had it been necessary. It was only used for riding with my mom and never really went off the beaten path. Given all that, I felt it was sufficient.
Coming back to the topic of the thread, the new Transalp, I just don't get writing it off over it having tubes. It's an adventure touring bike that's ostensibly designed to take you to out of the way places. That means the need to be able to effect self rescue in the foreseeable, if somewhat unlikely, circumstance of getting a flat. Already expecting to have to change a tube just ensures you'll be prepared for that. I fail to see how it's a major downside or a good reason to write off an otherwise good looking bike.