The majority will become motion sick. I've been demoing VR experiences on stands many times now over the last two years and FPS experiences creates that result in the majority. Even if it produced motion sickness in 'only' 10% that's a way too high number. Offer an obfuscated mode hidden behind security messages for people like yourself but don't (significantly) damage the majority.
Unless you were keeping tallies of how many people tried the experience and how many people felt motion sick, you'll forgive me for not taking your 'majority' claim as a fact. I've also demoed VR to a lot of people, but you'll notice, I make no such claims. Some got motion sick, some didn't.
Oculus will continue to rate games by a comfort level. Just as they do on Oculus Home on the Gear VR. I don't see the need for anything more than that. We all want VR to succeed. People may well be wrong to want first person games controlled by analogue sticks, but they want that. Letting them see for themselves that it's not the best solution in many cases isn't that bad.
And there are those of us that love it. By the sounds of things, this defaults to the home theatre mode. People who jump into first person and start feeling horrible, will jump back to the home theater most likely. Or play something else.
I've heard from the people demoing Adr1ft that most people *don't* get motion sick playing it, and that's probably the worst case scenario I can think of. Maybe they're wrong. Maybe you're right... but throwing around absolutes or claims that most people do or don't get motion sick doesn't help anyone.
People want this option. Some of those people will change their mind once they play a game that uses it. Some of us already know we won't.
VR is something that's going to find an audience either way, and I honestly think that in time, more and more people will be comfortable with artificial locomotion (just as apparently over time, car sickness has become less and less a problem). It'll never fully go away. Already there are people who get motion sick playing FPS games on standard displays, so I'm sure there will always be more people who get sick playing the same kind of game in VR...
Building things in minecraft is a perfect fit for roomscale VR, and I hope we see it. Exploring minecraft worlds that other people have made is something I'm going to want to do without having to resort to teleporting everywhere.
VR is going to have disclaimers left right and center. I don't see any need to bury options. Just don't default into the thing that's more likely to make people motion sick.
Temple Run VR on the Gear VR has one of the lowest comfort ratings on the store. It's also one of the most played titles on the platform.